The Nano Reef: a Step by Step Guide


Large Fish
Sep 2, 2004
Shelby, NC

The purpose of this article is to provide a how-to, step-by-step guide at starting your very own "nano reef." It is quite long, but hopefully this will furnish the beginner with the basics and give her a better understanding of starting a new nano tank. I've written this for people who want to keep corals, but if you're interested in a nano fish-only system, the information is much the same.

If you want to get to the nit and gritty of this piece, please scroll down to the section entitled Beginning Your Nano Tank, which will give you a complete walkthrough for starting out.

You've no doubt heard saltwater is difficult, expensive, and not easily forgiving. You've probably also heard "bigger is better." While it's true larger tanks have their advantages, they are not necessarily better or worse than smaller systems like ten and twenty gallons.

One of the best things about "nano" tanks is they almost entirely focus on the natural method of reef keeping. Your corals live and thrive through natural live rock (the "dead" skeleton pieces of reefs, which we'll talk more about later), strong water movement, and powerful lighting to simulate the natural illumination of the sun.

A Brief History of the Reef Tank

The reef aquarium as we know it today has come a long way from its infancy in the 1960s. So many things we take for granted today like glass and silicon aquariums without any metal parts, safe, reliable, and functioning heaters, and efficient and quiet hang-on power filters were unheard of in the early days of the marine hobby. As you can imagine, this made life for marine hobbyists a constant uphill battle.

Keeping corals and most invertebrate life was usually impossible due to primitive lighting, lack of availability of synthetic ocean salt mix, and largely no understanding of the nitrogen cycle and beneficial bacteria which breaks down ammonia and waste. Hobbyists largely kept damselfish and gobies, small and hardy fish which could withstand the poor water conditions of the era.

However, light emerged from these dark ages, ultimately foreshadowing the sucess of reef keeping today and the importance of imitating nature. Writer and long-time reef aquarist Mike Paletta tells us:

A hobbyist in Indonesia named Lee Chin Eng was using a rather elegant system that was called the "natural system." Mr. Eng used materials he could find close to his home near the ocean. Once his tanks were filled with fresh ocean water, Eng decorated them with pieces of old coral rock he collected from the lagoon. The rocks were called "living stones" and contained coralline algae, sponges, tunicates, shrimp, crabs, small colonies of coral and so on. A small number of colorful fish also inhabited his tanks.

The tanks were placed where they received at least some natural sunlight every day to provide illumination. The only technology he used was a small air pump that bubbled slowly. This provided light aeration, as well as some moderate water movement.

For their time, these "natural system" aquariums were spectacular. Despite the lack of technology, these tanks mimicked the reef to a much greater extent than any other type of system that had come before. Unfortunately, whem hobbyists in other locales tried to replicate this system they generally failed [due to not using the crucial "living stones"], so this method was dismissed as being unreliable or unworkable. (Paletta)​

The 70's largely saw more of the same. Dead coral skeletons, now commonly called "the graveyard look," were popular and this period saw many celebrities and people of affluence tackle saltwater aquariums, often spending tens of thousands of dollars on elaborate systems to flaunt their wealth.

The 80's were the age of big hair, big tanks, and big advances in the hobby. High intensity lighting entered the scene, as did superior understanding and execution of filtration. Paletta states:

The captive husbandry of marine invertebrates was changed forever by a series of articles is SeaScope in 1985 and FAMA in 1986. In these articles George Smit introduced the wet-dry or trickle filter to North American hobbyists. The articles changed the hobby because for the first time they illustrated, step by step, how one could keep marine invertebrates alive. Smit explained that just like on the reef, the foundation for a successful reef tank was the live rock upon which it was based. He also explained how strong illumination is necessary to keep corals alive, because light is the main source of energy for many of the photosynthetic invertebrates. (Paletta)​

The 1990s saw an an incredible number of advancements. Saltwater aquariums became much more mainstream and the reef side of the hobby exploded as new technological advancements were discovered and new schools of thought emerged. One such methodology was the "Berlin Method" of reef keeping which focused on live rock, powerful lighting, and strong protein skimming for nutrient removal.

Live rock was realized to be the "secret ingredient" of reef keeping, and protein skimming--the removing of dissolved organic compounds by utilizing the charged polarity of protein itself and air bubbles to collect the waste foam at the surface--helped keep water clear while removing excess dissolved organics before they broke down to burden the "living rock" filter.

As the hobby progressed through the nineties, smaller and smaller captive reefs were appearing. The smaller the system, the more "natural" they were: they used strong lighting (we'll discuss lighting in detail later), good water movement, and plenty of live rock to provide natural filtration.

Eventually the term "nano tank" sprang into existence. A nano tank is any saltwater system under 40-30 gallons. These small micro-systems were thought impossible by many experts and guru hobbyists of the early and mid nineties, and they are even frowned upon today by several respected names, including aquarist Bob Fenner, author of the popular The Conscientious Marine Aquarist.

Nanos did not truly take off in the mainstream until the 90's concluded. When I began my ten gallon, I borrowed two books from the public library, one published in 1999 and the other 2003. Both books were amazingly lacking in information--the gap between what I was reading and what I had learned on the Internet was so wide it almost felt like the book had been published in 1979. Even the 2003 publication stated tanks under 40 gallons were near impossible to maintain!

I actually began my journey into nano reefs almost immediately following the purchase and setup of my first freshwater tank. My wife Leah was intrigued by saltwater and took most of the research on herself. After a week or two of reading articles from the supposed top minds of the reef hobby, we decided a nano was a bad gamble, because we simply did not have the money, the space, or the free outlets for all the expensive and maintenance-hungry equipment needed to keep a nano up and running.

And this was in October of 2004, if that tells you anything about the evolution and advancement of the hobby!

To make a long story short, Leah and I were taking for gospel bad information espoused by so-called expert "heads" of the hobby, guys whose names you'll find on big shiny hardback books that cost up to $40. What finally got my feet wet in the reef hobby was my friend Justin Donaldson, who had set up a 29 gallon reef of his own in 2003. Through my friend Flave Hart, I learned exactly what was needed to make a successful mini-reef.

A ten gallon nano reef can be a wonderful alternative to spending several thousand dollars on a larger, equipment-heavy, traditional reef system. There are 4 natural elements crucial in starting and maintaining a nano:

  1. Biological filtration through live rock.
  2. Several jets of current to keep the water relatively turbulent.
  3. Strong fluorescent power compact lighting so the corals can photosynthesize.
  4. Weekly water changes to add trace elements as well as remove old water and "refresh" the system. No protein skimmers, pre-drilled or "marine" ready tanks, complicated overflows or sumps with networks of PVC, or $400 metal halide lighting needed!
Next we will discuss the pros and cons of nano tanks before diving into how you can set one up and be on your way to enjoying a tiny piece of the ocean in your living room.

Works Cited
Paletta, Mike. The History of Reef Keeping from a Hobbyist Point of View: A Personal Journey through the Hobby.

Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:


Large Fish
Sep 2, 2004
Shelby, NC
A nano reef tank is not for everyone. For instance, if you're hoping to keep large fish like tangs and the more aggressive saltwater angels, then you'll want at least a 55 gallon tank to host these fish.

Like any contained reef venture, a nano tank is a serious investment, no different than the larger, more traditional 55 gallon+ cousins. Be prepared to spend up to $300-$350 all told in setting up the tank: buying powerheads and salt mix, introducing the live rock, and buying a fish or two and some basic "starter" corals when the system is established.

Fortunately, a nano reef is dirt cheap when you compare it to a 55 gallon marine ready tank, which requires a sump, plumbing, the built-in overflow, specially designed stand, and often an expensive protein skimmer. This setup could run you anywhere from $500 to $800 on the basics and equipment itself.

But nanos have their disadvantages, too.

Below is a list of pros and cons you should keep in mind before committing to a nano reef.

  • Nano tanks are unequivocally cheaper than their larger counterparts on all fronts. (I.E. live rock generally runs anywhere from $7-9 a pound depending on the quality of the rock, and you need approximately one pound per gallon to maintain a good bacterial filter bed.) Opponents often argue you'll end up paying more due to loss of fish and livestock because water parameters are allegedly much less forgiving than they are on larger tanks. However, if you start right and know what you're doing, this factor will not come into play.
  • Protein skimmers are not necessary on nano tanks.
  • Equipment in general is very minimalistic. Bare bones, all you need are a couple of powerheads, a heater, and a powerful light if you want corals. However, a FOWLR (fish-only-with-live-rock) tank doesn't even need the expensive lighting.
  • Lighting is MUCH more affordable on smaller tanks. Expensive metal halides, the best and most powerful form of lighting for large reef systems, are bad choices for nanos. They heat up small volumes of water and can actually burn many corals, causing them to bleach. In nanos, you can often find one fixture of powerful lighting, often less than $120, to supply ample light for all manner of corals and light-hungry clams.
  • Nanos are much easier to move and break down than larger marine systems, with all their parts, plumbing, and under-tank apparatus.
  • KISS. "Keep it simple, stupid." You couldn't keep it simpler with a nano. No plumbing to worry about, no sumps or overflows, and a relatively minimal amount of electricity contributing to your power bill.
  • Your choice of fish and corals is limited. For a ten gallon tank, for instance, you will only be able to keep a fraction of the fish species available to the hobby. Gobies and clownfish are staples to nano reefs, but the larger reef safe fish like tangs are not suitable for small systems because they grow large and need open spaces for swimming. Also, many corals cannot be mixed in small volumes of water, due to chemical warfare among soft corals and sweeper tentacles among LPS.
  • Evaporation is brutal on a nano tank. Often daily top-off of freshwater is needed to keep the salinity constant. Water naturally evaporates into the air, but the salt remains in the water, raising the tank's salinity if freshwater isn't regularly added. Nano tanks require daily or every-other-day top-off with pure freshwater.
  • Good water is crucial to nano systems. Often tap water is horrible for the reef tank as it contains nitrates, phosphates, and a bunch of other undesirable elements which could turn your little ocean garden into an algae free-for-all. I personally only use RO/DI water for my nano. RO/DI is a fancy way of saying reverse osmosis and deionized water, which is freshwater that's had 99% of its trace elements and even more pollutants removed through special filtration. This water is ideal for nano reefs. I personally would use nothing less.
  • Temperatures can soar in the summertime if you don't have air conditioning. An open tank (the light fixture jacked or suspended two inches above the rim) is a must if your house swelters in the summer.
  • Nanos require extra attention. In other words, they need to be looked after more than larger, more complex systems. I personally do not like leaving my ten gallon nano longer than two days without attendance. If you're leaving for a 3-day weekend, for instance, it's best you give your keys to a trustworthy friend or neighbor to top off your tank with a bottle of RO/DI water and know what to do in case a fish dies or some catastrophe happens.
  • Anemones are generally very bad choices for nanos. The smaller you go the more difficult and inappropriate they become. The majority of commonly available anemones grow too large for a 10 or 15 gallon. They are also very aggressive, especially the carpet anemone. They will sting your other corals and move about the tank at will. They will also likely eat your fish. I personally would not try an anemone in anything less than a 30 gallon long tank.
Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:


Large Fish
Sep 2, 2004
Shelby, NC
Beginning Your Nano Tank

Okay, now that we've gone over the pros and cons of keeping a nano, we're ready to dive into the how of nano keeping. The secret to being a successful reef keeper is reading all you can about the subject and making your own educated conclusions. The Internet and Google are perhaps the best tools for reef keeping, as new technologies and schools of thought are discovered and shared all over the world at an incredibly rapid pace. A good book will also help you, but it's certainly not needed if you have regular Internet access. And I've yet to read a good publication on setting up and caring for nano reefs.

We'll start with the basics: your tank, equipment, and substrate.

Your nano can be as small as 1 gallon or as large as 40. Anything larger than a ten gallon is best placed on a stand designed to hold the tank's weight. Often small tanks come as part of a kit which includes the stand.

We'll be describing a walkthrough for a ten gallon, which is a relatively small but respectable size. Don't worry if your nano is larger or smaller, the same principles still apply unless otherwise noted.

Next you'll need a heater, rated approximately 50-100 watts for our ten gallon (if you're starting a twenty, try to find a 150-200 watt heater, a 50 watt for a five gallon, etc. -- also, for any system below 3 gallons, the powerhead will generally keep the tank in acceptable temperature ranges). The best heaters are Ebo-Jagers, but I've also had good experiences with Marineland's Visitherm heaters. These heaters are submersible, meaning they are placed entirely under water.

Water movement is crucial and usually the stronger the better. For our ten gallon we will be using two powerheads, placed at opposite ends of the tank and blowing to a central point. Any powerhead rated 70-150 gallons per hour is good. Try to find a 120 of 150 gph powerhead for one end of the tank and 120 or something slightly less powerful for the other.

You can also use a hang-on-the-back power filter for additional current. These are good because they offer a venue to run carbon, which pulls chemicals out of the water. I run a Penguin mini with a biowheel on my ten gallon along with two powerheads.

Note: you do not want to use any filter cartridge. For saltwater, these are nitrate factories.

Strong currents keep live rock free of detritus and eliminate dead spots, which are breeding grounds for slime algae, the dreaded cyanobacteria.

Now for substrate, or what will cover the bottom of the tank. Bare bottom tanks have their benefits but they are unsightly and a lot of good dentrivores (tiny scavengers) live in the sand at the bottom of your tank.

Here are 3 options for substrate:
  1. Aragonite sand
  2. Crushed coral
  3. Play sand
Aragonite is the most expensive of the three, used by the majority of marine hobbyists. It is often a fine sand which will help keep your tank buffered at the correct pH, which is important for keeping a successful reef tank.

Crushed coral also buffers the water, but it doesn't go as high as aragonite. Crushed coral is more affordable, but the price difference really isn't that much. Crushed coral is more coarse than aragonite or other sands, resembling white gravel. I currently use crushed coral in a 7.6 pH freshwater tank.

Play sand is by far the cheapest option. You can find this at large home improvement stores. While there are aragonite based play sands, they are not always available. Most play sand is silica based, which many reefers believe cause algae outbreaks. I personally use silica based play sand and I am quite satisfied with it.

You'll also see something called live sand. This is sand that's enriched with good living bacteria. It's certainly not harmful, but it's not necessary because your live rock will make your dead sand living sand in short order.

Approximately 1 pound per gallon is good. Deep sand beds have their pros and cons, but a lot of sand takes up a lot of real estate in a small tank!

All substrate needs to be thoroughly rinsed. A paintbag or a pillowcase works well, although using a bucket and a hose will also work. Let the water run clear before adding to your tank. (Note: If you add your substrate first, be sure to clear the area where you place your live rock if you stand it vertically, to create a more secure foundation for the rock to stand on--the important thing is to make sure your rock can't fall into the glass, and you definitely do not want it leaning against the glass at all.)

Don't worry about lighting for now. If you're not planning on keeping corals or photosynthesizing invertebrates, standard fluorescent lighting will do fine. However, it's best to run an open tank to keep the water cool as well as prevent a lot of salt creep (dried salt that collects on top of your tank). Salt creep is annoying and requires routine maintenance to clean it from the edges of a hood.

Your First Trip to the LFS

Now that your tank and stand are set up, and your equipment is ready to get wet, it's time to visit the LFS (live or local fish store).

Heed this quick warning before we proceed:

Unfortunately, many LFS' are unscrupulous in selling you a lot of stuff you don't need, fish and inverts that won't live in your system, and unnecessary additives that may even harm your tank. This is why it's so important to know exactly what you need before you go into the store.

Here is a list of what you'll absolutely need to get started:

  1. Salt mix. Instant Ocean is a good brand, and cheap. Do not let the LFS try to upsell you on a more expensive brand.
  2. A hydrometer. Hydrometers are instruments that read the specific gravity of sea water, letting you know the water's salinity level. A more expensive instrument called a refractometer is much, much more accurate and ultimately a very wise investment.
  3. A pH test kit. Be sure the test kit reads the high end of the pH spectrum, above or to 8.6.
  4. Live rock. Here's the fun part. Try to shoot for a pound of live rock per gallon. Live rock comes in all shapes, sizes, and colors. We'll discuss this in detail later.
Saltwater test kits for ammonia, nitrite, and nitrate are also very important, especially during the first weeks and months. I highly recommend all three test kits, with ammonia being the most important. Be sure you pick up tube-and-dropper test kits that are rated for saltwater.

Do not, I repeat, do not let the LFS worker try to weigh you down with additives, supplements, or whatever gimmick of the week they've bottled up. Most of these things are overpriced junk. Marine fish stores make most of their money through additives, if that tells you anything.

Also let me further emphasize how bad LFS's can be and tell you right out that the product Cycle does nothing. I've heard LFS workers baldly lie to customers, telling them they've used it on their livestock tanks and display tanks to get them "cycled" and ready for aquatic life. I've personally seen a doomed 20 gallon nano go down in flames with Cycle being the arsonist.

A "cycling" product is not needed, anyway. Your live rock will cycle your tank in a period of 1-2 weeks.

Here's a blacklist of things to avoid that your nice LFS may try to get you to purchase:

  1. Reef supplements. While corals may be in your future, right now they are a good distance away -- and often a thriving nano reef doesn't need special "reef" additives or supplements and thrives just fine on its own. Some of these reef additives include supplements for alkalinity, calcium, pH, strontium, iodide, etc. I personally don't use any additive whatsoever for my nano reef. Regardless, you're just starting out and you simply do not need any of these things.
  2. Reef or marine tonics. These are "fair weather" medications that have names like "Healthy Reef drops" and "Ocean Boost." Don't listen to the LFS if they say you need these things, or if they say a) they use them in their shop tanks or b) use them in their own personal tanks at home. If they're not downright lying to you, they probably don't know what they're talking about. While it's true that a product occasionally comes along that may be helpful, most of these things are gimmicks and do very little good.
  3. Fish or livestock of any kind. Often following their attempt to sell you Cycle, some LFS's will try to get you to come home with a fish on your first day. Do not do this. Don't even buy a reef hermit crab. Your tank is brand new and it takes time for the live rock to establish itself. Some stores still sell damselfish to cycle new tanks. This is absolutely not necessary and can be very detrimental to your tank... damsels are aggressive and a bad choice for nanos, unless you're doing a damsel-only tank.
There are some wonderful and honest LFS's out there, but I'm sad to say that most are not straight shooters. When you find a good LFS, stick with them and give them your business, buying salt and equipment from them as opposed to large franchise stores that often put good LFS's out of business.

Next we will discuss live rock, and yes, we will be getting wet!

Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:


Large Fish
Sep 2, 2004
Shelby, NC
Livening up Your Tank with Live Rock

Live rock is perhaps the single most important factor in keeping a nano reef, or any captive reef. Live rock provides natural biological filtration in the form of microscopic bacteria living on and within the rock. Live rock also breaks down nitrate deep within the rock in anaerobic conditions.

Live rock is usually coralline algae-covered rocks or dead calcified coral skeletons. Despite its name, live rock is not part of the living reef. It's actually rubble from reefs either long dead or broken free during storms. Although live rock is no longer part of the reef, the rock continues to host a variety of life.

The bright and interesting colors you see on good live rock pieces are coralline algaes, a beneficial encrusting algae which helps against troublesome algae by outcompeting it for nutrients. These colors, along with the attractive shapes of live rock, make live rock very aeshetically pleasing for the reef tank. Even if you elect not to go for a reef tank, live rock will give your tank the "reef" look.

When shopping for live rock you'll likely find multiple varieties, given names specific to their native locales. Some of the most common varieties are rocks that hail from Fiji, the Tonga and Marshall Islands, the Caribbean, and Florida. The best live rock is porous and lightweight, allowing maximum surface area for bacterial colonization. Try to avoid the bulky, heavy pieces.

You'll also see live rock offered as "premium" pieces. Usually these are rocks teeming with good algaes and life, often completely red or purple from coralline growth. Obviously, these are higher priced because they are prettier and supposedly give you more bang for your buck with greater microorganism count.

The important thing is to pick out several pieces that you really like. Be sure the live rock is cured. Cured live rock is rock which has sat in the LFS' curing tanks for a month or two, eliminating most of the natural die-off of organisms which can pollute your tank. Uncured live rock can cure in your new tank for up to a month and a half and will require frequent water changes as the rock establishes a new bacterial base.

Two or three large 3+ pound pieces are good for a ten gallon nano. I began mine with only nine pounds. I now have a total of twelve pounds. Often you'll buy coral already secured to a piece of live rock so keep that in mind as you select the rock and make your future plans.

It's important to place your live rock securely on the substrate. This means you make sure it does not wobble enough that there is a chance for it to fall, potentially into the glass. Of course, that goes without saying, do not lean live rock against the glass. I've learned the hard way that it's best to use zipties or other means of securing two pieces together if you lean them against one another, vertically. It's no fun righting a fallen piece of Tonga branch that already has a clam attached to its supporting rock.

Your live rock can go straight into your tank once it's ready and the powerheads are running. And if you've already laid down your substrate, don't worry about placing your rock on top -- just be sure it's firmly in place in the sand and won't collapse or fall into the glass.

Follow the directions on your package of salt mix and prepare your first batch of synthetic seawater, checking the salinity with your hydrometer or refractometer. Aim for a number between 1.022 and 1.026. I keep my reef at 1.022-23. The important thing is keeping the salinity constant. Remember specific gravity is relative to temperature, so be sure the water is heated to 78-80 degrees when you check.

A Word about Lighting

(Note: If you're keeping fish only and live rock, you can skip this part.)

Good lighting is as important as live rock for reef keeping, if not more so. Without adequate light, corals will ultimately close up, wither, and die. Unfortunately, reef lighting is very confusing for the saltwater beginner. Those "Marineglow" and "Coral Sun" bulbs at Petsmart and Petco will not light a nano reef, despite the claims written on the box. Unless you have a 1, 2, or 3 gallon tank, a single bulb will likely not allow you to keep even the hardiest of corals.

Corals do best in lighting in the 6700-10,000 kelvin range. Kelvin is a measurement of heat, and the temperature yields a certain color on the spectrum of visible light. Do not confuse this with nanometers, which measures the wavelength of light color in the visible spectrum.

Okay, let's break it down...

  • 6500-6700 K: This range is ideal for freshwater plants and also good for corals. This is a soothing, almost institutional white.
  • 10,000 K: Generally better lighting for corals. 10,000 K offers a very crisp, bright, white light.
  • Actinics: The blues of reef lighting. Think of a blue flame... much hotter than an orange flame, right? Same applies here for lighting. The kelvin rating is much higher for "actinic" blue light. Actinics, when combined with 6700 or 10,000 K bulbs, creates a very pleasing look for the reef tank. Most light fixtures offer a 50/50 mix, which is an actinic light coupled with a white light.
The benefit of employing a ten gallon reef is that you can easily have approximately ten watts of light per gallon, which is enough to keep almost any nano-appropriate coral or clam. I use the 96 watt Coralife quad light 20" fixture with 50/50 bulbs. This kind of fluorescent lighting is called power compact, a regular fluorescent bulb which is bent in half to double lighting power.

Power compact bulbs are best if changed every 6-10 months. The bulb will continue to illuminate, although it loses a lot of its punch over time and can eventually weaken your corals if not changed.

If you're planning an unorthodox nano tank, like a large bowl or a vase, Coralife also makes a 10 and 20 watt 50/50 compact fluorescent bulb, ideal for micro or "pico" reefs. These bulbs screw into lamp ballasts like a normal incandescent light bulb.

Patience is Key

You have your tank up and running, the live rock has been introduced, and your heater light is on, keeping your water in safe tropical temperatures of 77-82 degrees. Now it's time to sit back and watch all the cool life that will emerge from your live rock.

Lighting is not needed during this time, and many hobbyists believe it's best to go dark while your cured live rock goes through a phase or two of die-off, in order to keep nuissance algae down. So now would be a good time to buy or order your reef light. Three excellent online retailers which offer whole reef lighting kits are,, and

No matter how "cured" and life-rich your rock is, you will go through a period of die-off. Algaes may peel off in brown ugly lumps, or a dead starfish may suddenly appear in your tank, having floated up from the depths of a rock. During this time it's important not to add any other life. Trust me, in one or two weeks, your tank will be ready to host your first little lifeforms, called the "clean-up crew."

If you're buying your live rock piece by piece, buy your largest pieces first and try not to add any crabs or snails until they've had a chance to establish themselves.

All live rock is different. You may have a piece or two that hadn't cured all the way and may have to wait up to three weeks before adding the clean-up crew, or you may be ready in three or four days. A good rule of thumb is to wait 10-14 days while checking your water for ammonia and nitrite. To be safe, you don't want to add any crew members until ammonia and nitrite fall to zero.

Fortunately, "cycling" a marine tank is nowhere near as boring as "fishless cycling" a freshwater. You'll see clear, tiny flea-like critters on the rock and glass, which are called amphipods and copepods. These are very desirable and provide essential fatty acids to your fish when they are consumed. You'll also see a small bristleworm or two, maybe a featherduster, tiny little white starfish, and if you're really lucky, a coral may have stowed away.

These forms of life are called "hitchhikers." They can be good and bad, and there are so many it would be impossible to list them all.

Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:


Large Fish
Sep 2, 2004
Shelby, NC
The Clean-Up Crew

You're probably noticing a little algae in your new tank. Most likely it's brown algae, or diatoms. Fortunately, you'll see how fast your clean-up crew will take care of this unsightly sludge.

It's been a week or two and your water readings are clear, so it's time to head back to the LFS and buy your cleaning invertebrates, reef hermits and snails.

Reef hermits are the tiny hermit crabs which live in shells. They often have red or blue legs, but they can also be striped, brown, or green. These guys eat diatoms, help sift the sand, consume uneaten food, and clean detritus in live rock. A good number to have is 1 per every 2-3 gallons.

Also, ask your LFS if you can get some empty shells too. Usually they will oblige. If not, check out a craft store and look for small shells, with openings the crabs can fit into. Be sure the shells haven't been treated, dyed, or sprayed with excess chemicals.

To clean the glass you'll need snails. There are many types of snails available for the marine hobbyist, but not all of them are ideal for nano reefs -- like the turbo snail which gets large and can knock over corals.
  • Astrea snails stay relatively small but can clean a lot of glass. It's good to have one astrea snail for every five gallons.
  • The much smaller and conical cerith snails burrow in the sand and help keep your substrate from developing anaerobic pockets. They also reproduce very easily in the reef aquarium.
  • Nassarius snails are also good burrowers. They are incredibly fast, and it's a lot of fun watching them burst out of the sand like zombies when food is added to the tank.
  • Margarita snails stay small and are rumored to even munch on the very annoying green hair algae.
Eventually you may want to add a starfish or two to your reef tank. Starfish are much more sensitive to water parameters than crabs and snails so it's best to wait until you've bought fish and then introduce a star. Some nano reef safe stars include:
  • Brittle stars (watch out for the green variety, they may attack fish and corals).
  • Serpent stars.
  • Fromia stars.
  • Blue linckia stars, though they are big and can knock over corals.
The hardiest of the lot mentioned above are the brittle and serpent stars.

They are much faster than fromias and linckias and easier to feed. They also can be exposed to a brief amount of air during acclimatization.

Until your starfish joins the feeding frenzy during meal time it's best to feed these creatures yourself with a wooden skishkebob skewer and a tiny piece of shrimp or fish food.

Shrimp are the same deal as starfish. It's best to wait until you have fish to add shrimp.

Fish Time

It's been 1 to 2 weeks since you've added your clean-up crew. Maybe you're starting to see some feather worms or spaghetti worms emerge in your rock, and your substrate doesn't look as "clean" as it did when you started out. Your tank will continue to establish itself for the first 6-8 months, but it's been a month now (maybe a little more or less) and you are ready for your first fish.

Now a word about a quarantine tank. It's always best to have one of these, if possible. For our purposes with a nano system, a 5 gallon will do. Q-tanks are very bare bones, with a bare bottom, a powerhead or better yet a HOB filter to use carbon in the chance you use a medication, and a plastic plant or a terracotta pot or two for the fish to feel secure. You can use some live rock rubble to cycle the Q tank, but remember if you use any copper based meds or antibiotics this will wipe out your bacterial base within the rock.

Keep the fish in the Q-tank for 4-6 weeks before introducing it to your main nano.

Ok, so you've Q'ed your fish or selected one to go straight into your nano (always a gamble). Now it's time to talk fish!

For our ten gallon nano our selection of fish is limited--however, you still have a fairly wide list of fish from which to choose.

Clownfish, true and false perculas (ocellaris clowns), are often found in ten gallon nanos, either solo or in a pair. Despite what you may have heard, clowns do not need to be in a pair to be "happy," nor do they need an anemone to host in. If you elect to have a pair as your two fish, then buy them small and close to the same size, and it's okay to buy your two clowns for your "first" fish. Clownfish are capable of changing sex, but mixing a larger, older clown with a smaller one is never a good idea in these close quarters.

I recommend keeping no more than 2 "small" fish in a ten or fifteen gallon (a tank that takes up the same footprint as a standard ten). Small fish for saltwater are those that grow no more than 4-5 inches. For example, true and false perculas are good, but maroon clowns are not, because they grow significantly larger and are also much more aggressive.

For a twenty gallon tank, three fish is a conservative number, though four will also work. For a twenty gallon long, four will work nicely. You could even have a dwarf angel in a 29 or 20 gallon long.

In my opinion, a five gallon can host only one fish, maximum. However, there are many successful nano reefers who keep two small fish in five gallons, so do your homework and make your own decisions.

I'll also state I don't think it's a good idea to keep a fish in anything under 5 gallons. As a keeper of a "pico" system (a micro nano, if you will) that only has one gallon volume of seawater, I know what can be pushed and what can't through experience. I have personally tried keeping small shrimp in my pico during different times of the year and all have died within a month. However, once again, I've seen nano reefers keep one tiny fish in a 2.5 gallon reef, so it is possible, but... caveat emptor.

The reason why I believe fish shouldn't be kept in "pico" systems is because temperature fluctuations and the bioload of the fish are just too unstable for these tiny tanks. I only keep snails, a reef hermit, and hardy soft corals in my pico... all thrive, and they are very enjoying to watch, so don't think you need a fish for a fun and interesting nano!

Below is a list of fish which will thrive in most nano systems (from 5-29 gallons and up):
  • Gobies
  • Royal Gramma
  • False Percula Clownfish
  • True Perculas
  • Green Chromis
  • Bangai and Pajama Cardinalfish
  • Blennies
  • Six-line Wrasse
  • Dwarf Angel
Several of these fish do not get along with others (and some expensive invertebrates as well), so please read up on them on MFT's profile section or at

The list is certainly not all-inclusive. It's a good starting point, nothing more.

You also want to be 100% sure your fish is reef safe, if you're planning a reef in your future. Some, like the six-line wrasse, will eat your reef hermits and other invertebrates, and they also may be difficult feeders at first. Six-lines are also aggressive and will probably terrorize your other fish in a nano tank.

Think of all saltwater fish like the freshwater oscar: not the oscar's large adult size and his capacity for eating any fish that could fit in his mouth, but instead think of how one must carefully consider tankmates for this fish. Clownfish are aggressive eaters and may not mix with other species in close quarter settings. Damsels, while being nano-reef safe, are especially vile, nasty little monsters, and the domino damsel will likely kill or stress a clown, goby, or royal gramma to death.

Here's another general, starting point list for possible fish combos in our ten gallon:
  • A firefish and a true or false percula
  • A pair of true or false perculas
  • A percula and a blenny
  • A mix of two gobies (note: mandarin "gobies" are actually dragonetts and not true gobies. While a mandarin may work in a nano, the nano reefer must fully understand what the mandarin needs to thrive before trying to keep one)
  • A royal gramma and a cardinalfish
The important thing to consider with any fish is its full adult size and its compatibility with a reef or invertebrates like clams and crabs. Also feeding is an important consideration. Clowns and gobies are generally very easy feeders, meaning they will accept pellets, flakes, frozen, and live food, but some fish like blennies and the six-line wrasse can be difficult to get feeding.

Is a fish or two the main goal of your nano, or is it the reef itself? Please consider this question before selecting your fish and proceeding with the reef element of saltwater keeping. If an extreme reef bursting to the seams with corals is your dream, then it's best to stock only one fish.

Thankfully, saltwater fish are much more personality driven than their freshwater counterparts, and even one small goby will keep you entertained and happy.

To be continued with corals, special information for small "pico tanks", and final thoughts...

Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:


Large Fish
Sep 2, 2004
Shelby, NC
The Nano Reef

You've got your live rock. You've got your strong power compact lighting (at either 65, 96 watts, 50/50, 10,000K's, etc.). Water parameters are stable and nitrate is (ideally) under five ppm. And your fish or two are doing fine.

A new tank doesn't truly become established until you reach the six or eight month mark. Some people say a year. During this time you'll see a number of algae outbreaks, ranging from bryopsis hair algae, green bubble algae, and red slime cyanobacteria. Often improved water flow will help out, but sometimes when an algae takes root it stays stubborn.

Unless it's cyanobacteria, don't get too hung up on a patch of hair algae here and there. Algae is part of life in a reef tank, and even ugly green hair algae helps to export nitrates (as long as it's bright and alive--if it's dull, slimy, and brown, it's dead and adding to nitrate production). The important thing with algae is balance: green hair algae and any other algae can take over a tank and if the scales tip in its favor, you need to address the root cause and bring the balance back.

Since we're talking algae, now would be a good time to segue into corals. Algaes are plant life and corals are animals, despite their plant-like appearance. Like algae, the reef-building corals we see in the hobby receive most of their nutrients, which they convert into energy, from the sun. This happens because microscopic symbiotic algaes called zooxanthellae live inside them and photosynthesize. This also happens within the mantles of clams.

There are three kinds of corals available to the hobby, commonly called soft corals, small-polyped-stony corals (SPS), and large-polyped-stony corals (LPS). In larger tanks, you can mix these, no problem. However, the smaller the tank, the more risk in combining them as chemical warfare is much more exact and undiluted in smaller volumes of water, and sweeper tentacles from some corals can damage their neighbors, even if they are five to six inches away.
  1. Soft corals are generally the best suited for nano tanks (green star polyps, zoanthids, and mushrooms can live and thrive in nanos as small as 1 gallon). Soft corals get their name from their lack of "stony" skeleton and mushy texture all the way through. They are the least light-hungry of the three, and they are also the easiest which makes them excellent beginner corals. Some popular soft corals include zoanthids or button polyps, mushrooms, green star and starburst polyps, xenia, gorgonians, leather corals like devil's hand coral, and tree corals.
  2. SPS corals are the ones most people think of when they hear "coral" or "reef." SPS construct the calcified base of living coral reefs in the oceans. They require the highest lighting and generally do best under metal halide lighting. They are also very sensitive to water parameters.
  3. LPS corals include the open brain corals, torch corals, plate corals, and bubble corals. Their large, fleshy polyps grow from calcified skeletons, making them "hard" corals even though many of them appear to be "soft." These corals require feeding through their mouths and extend sweeper tentacles during feeding, making them dangerous if placed too close to other coral varieties.
Now that you're familiar with the basics, let's see if your tank is ready for an easy and beautiful soft coral. Is your nitrate stable under ten ppm, preferably under five? Does your pH remain constant? Do you have more than 3 watts per gallon of good lighting?

If you answered yes to all of those questions, congratulations. You're ready to turn your nano into a nano reef.

Zoanthids (button polyps) and mushrooms are excellent beginner corals. If you're buying your first coral from the LFS or from an online retailer, you'll likely receive a colony of corals on a piece of live rock. This is good because you can place that coral rock wherever you want in your tank. Zoanthids like moderate water flow, while mushrooms enjoy a little less. Both of these corals go easy on light so it's best to place them near the substrate.

Acclimate your new coral by floating the bag in the tank for fifteen minutes so the temperates equalize. Then open the bag and "drip acclimate" the specimen. You can use a piece of airline tubing tied off to regulate the flow, or you can use a plastic regulator to pinch the line for better control.

I drip-acclimate my corals for thirty minutes to an hour, depending on the sensitivity of the invertebrate. When the water in the bag has at least doubled, you're ready to introduce the coral. Gently pick up the rock, remove from the bag (these corals can be exposed to air for a surprisingly long time), and place where you want in the tank.

Transporting corals stress them so don't expect your zoos or shrooms to open up right away. Give them a day or two. Remember these corals are very hardy and can withstand a lot of abuse.

Like fish stocking, it's best to begin with one coral, then try another similar type in a few weeks. If you want to try to mix soft corals and other varieties, be sure soft corals are placed well away from the others. Also have an alkalinity test kit on hand as stony corals absorb much more calcium than softies. Same goes for clams, which can easily be stung by sweeper tentacles.

A Word about Micro Systems

Contrary to what you may have heard, keeping pico or micro reef systems is not just for the advanced hobbyist. I consider anything under a 3 gallon nano a "pico" tank. I keep a 1 gallon pico reef on my desktop and it is by far the most stable and easy system in my house to maintain. The only work I do for this tiny reef is daily top offs with RO/DI, 12 ounces of water changes three times a week, and the occasional rinsing of the Micro-Jet powerhead which makes this pico system possible.

As long as you understand the limits and daily attention a pico requires you'll be good to go.

As I've said before, determining if you want to start with a ten gallon reef, a 29 gallon, a five gallon, or a 2.5 gallon tank hinges on what you want to see happen in your captive reef. Are you looking for something that's relatively cheap, easy to take care of, and you don't want fish? Do you want something you can easily move and display on your desk, and do you like stunning your friends with cool, rarely-seen things? A pico would be right up your alley. Just be prepared to keep only an astrea snail, a reef hermit, and zoos, shrooms, and green star polyps. You may be able to keep a small shrimp like a sexy shrimp (or anemeone shrimp) or you may not. I personally have had no luck with shrimp in my 1 gallon due to the extreme temp. fluctuations during the day.

However, if you want to keep a nice mix of things, the ten gallon or fifteen gallon high nano reef is your best bet in starting out. If you like your ten and after six months you want to try something bigger (or smaller), you'll have some experience under your belt and you'll be good to go.

Final Thoughts

Nano reefs are the future of the hobby. What I mean by this is more and more people are beginning with ten or twenty gallon marine systems and freshwater aquarists are jumping ship, often turning an old ten gallon into a saltwater tank. These folks often do not have the funds or means to "start right," as some seasoned hobbyists claim, by putting together a 55 or 70 gallon system. They also never would have dreamed of having a saltwater tank, stuck behind the mental roadblocks unintentionally (and sometimes intentionally) put in place by the hobby at large.

These barriers that kept so many people away (like my wife and I) include myths of astronimical costs of setting up a saltwater system, marine keeping's extreme or outrageous difficulty, the necessity of metal halide lighting, jacking up of your electric bill, and reliance on chemicals and expensive equipment. The beauty of a nano tank is with a little research these myths vanish like a dream upon waking.

As long as you keep in mind the pros and cons previously outlined, a nano tank is no more difficult than a large system with its equipment, sump, and plumbing. And I'll take that to the bank any day.

Unfortunately, there are still many writers and publicists who claim nano tanks are foolish and/or money-pits and are doomed for ultimate failure, citing some nebulous reason like a water "crash," or too much nutrient build-up over time, or greed on the part of the LFS to rope in newbies. Think of these guys and this kind of thinking like the old-boy network in a country club, and you as a nano reefer are the new money walking into their turf.

Be proud of your nano reef. And be proud to be a nano hobbyist.

I would personally like to thank Justin Donaldson, Flave Hart, 1979Camaro, Aresgod, and S.Reef for their coaching, stellar advice, and one-on-one help. And most of all, I'd like to thank my wife for her initial research and helping me realize a saltwater tank is indeed possible.​
Copyright 2006 by Josh Day. All rights reserved. No part of this article may be reprinted or distributed to other websites without the author's written permission.

Last edited:
Dec 21, 2005
st. louis area
this is a great post. I have a question may seem dumb but how do you run carbon without the cartrige? I have a penguin mini on my 10g but I use the filter cartrige. I was misinformed. I don't use the bio-wheel because I read somewhere not to use it with sw. weird. So should I get a new wheel and toss the filter.


Large Fish
Sep 2, 2004
Shelby, NC
I apologize to everyone for not finishing. Unfortunately, the very morning after I had assembled the article, my computer failed, and I am only back online today. I have a lot of work to do to get my system back up to snuff but I plan to have the article finished by Sunday, hopefully.

ram man

Superstar Fish
Apr 16, 2005
Great job! when i first started this hobby i was told that it is near impossible to set up a nano, but your article tells all the things some one needs to know about keeeping nano reefs.


New Fish
Apr 7, 2006
Scottsdale, AZ
Thank you for this wonderful article. I've read and re-read it twice because I don't want to make any mistakes. I used the boxed saltwater, live rock and live sand. Probably overkill but I lost a 55 gallon tank and lots of fish years ago and I want to be sure to do everything right. Do you have any recommendations on a good brand of salt as the boxed saltwater is expensive, not to mention too heavy for me to lift. :) This is a great forum and I'm learning so much. Saltwater has really changed in the past 15 years. :)


Large Fish
Sep 2, 2004
Shelby, NC
Thanks Gina and everyone else for the nice words. Also I'm always revising the article... the more experience we all have the better, so if you have any suggestions, post them and I'll revise the main piece.

I use instant ocean. It's affordable and very reliable. In my reef club everyone uses IO, except for two people who use reef crystals, and one of them has done an experiment and really hasn't seen much of a difference.

So I recommend Instant Ocean :)

Likes: ram man


Large Fish
Feb 22, 2006
Kirkwood, MO
i agree with lordroad, go with Instant Ocean if you can. I've been using Oceanic brand lately and its been okay. my main thumbs up to Instant Ocean is I've never seen the slightest difference between cans. Can't say that about Reef Crystals.


Small Fish
Apr 22, 2006
I have an existing 50 gallon reef tank, and have just started my ten gal Nano. I have to say its just as much fun creating the Nano as it was the 50*celebrate . I think the Nano will be very rewarding in that the aquascaping is so in your face that the things one might miss in a larger tank are up close and personal. I cant wait to finnish this project so I can start my 3 gal Pico.*thumbsups