The Nano Reef: a Step by Step Guide


Large Fish
Sep 2, 2004
Shelby, NC
A six-line? I've never kept them personally, but I've seen a pacifist six line do fine in 29 gallons. Key word being pacifist. I think the problem with these guys lies in aggression. I've known several people both online and in real life who have lost fish and even clams to these fish.

Do you have a ballpark figure of what size tank were you looking to get, Ram?

Live Aquaria states they grow to 3 inches but I think in a small tank, anything less than 20 gallon long, there could easily be problems with aggression to other fish.

May 9, 2008
hi people, i have some questions for you,
it is possible to have a nano reef tank that do not be as bigger as a 2 gal tank??
what kind of filtration would i need?
would i need more than 2 power heads with filter included?
can i use a platform bacterial filter? or is it a beginner mistake?
please help me


Superstar Fish
Nov 26, 2007
Charlotte, NC
hi people, i have some questions for you,
it is possible to have a nano reef tank that do not be as bigger as a 2 gal tank??
what kind of filtration would i need?
would i need more than 2 power heads with filter included?
can i use a platform bacterial filter? or is it a beginner mistake?
please help me
I believe what your trying to say is that you want a nano that is under 2 gals. If this is correct then yes it can be done, but I don't believe any fish would really work in there. You would just have your live rock, some corals, and maybe a shrimp and a couple snails.

I think with such a small tank you could get away with only one powerhead.

Usually the live rock serves as a natural filter for a reef tank so I doubt you would really need a power filter or anything like that for a tank like this.

Cichlidman had a small tank setup for a little while, I believe it was 2.5g, and his looked really nice.

I have never done a saltwater tank before so I may be wrong with some of this info, but I have been doing some researching for a future tank. Instead of replying to a sticky, you might want to consider creating a new topic for these questions so they can get more attention.

Good luck

May 9, 2008
thanks alter40, it would be interesting for people who just have enough money for make a really nano reef tank to consider all possibilities for begin this phase of the hobby. I have one live rock, two real crabs (one of those looks like a prisoneer because it´s black and white), some red shells and one little annemona.
all had a price of US$13 aproximately, because i bought them in colombian coin (i´m from Colombia) and i´m just beginning in this area.
In the other hand I have a couple of oscars and they grow really fast giving them live food. I feed them with feeder guppies because they are not so big enough for eat a goldfish


Medium Fish
Mar 3, 2009

When i get my larger freshwater tank i'm thinking of converting my 10 to a saltwater. Love the article very infomative. Will i need to clean and throughly dry my ten before beginning. I have a small algae problem right now and don't want it to transfer over or is that even possible???/:confused:

Mar 10, 2009
Fantastic article! Very comprehensive.

A question about carbon: does it really help? What does it remove from the tank? I had heard that carbon in any saltwater setup was a bad idea because it can throw off the chemical balance of the salt water mix.




New Fish
Mar 14, 2009
Carbon usage in reef Nano

I have heard mixed opinions about carbon. True it can pull out harmful toxins that might be in the water, but also filter out beneficial elements as well. Being new with a 14 gallon Nano, I am confused as the rest.
But, as my Dad used to say, moderation is everything. So I have been using my Chemi-Pure bag in the middle sump for several days every couple of weeks. It seems a good balance. Any thoughts?


Medium Fish
Apr 28, 2009
Pinellas Park, FL
I just found out that my boss has a 24g saltwater tank with a lionfish! He said that saltwater tanks weren't as hard as I was thinking and now I kinda want to try one. I'm thinking 10g with a pair of clowns would be cool. I'm also thinking I'd have to upgrade my freshwater tank to a 20g first an where am I putting the new 20g... I've sort of maxed out my rooms capacity to hold furniture.

Last edited:

unwritten law

Superstar Fish
Sep 2, 2008
So i got an extra 10 gallon sitting around.... looks like its gonna be one of these.

I have an extra canister filter sitting around but I see that these don't necessarily need an actual filter? Or am I wrong on this. I was hoping that this canister filter (110gph) would be a nice substitute for at least one powerhead and then I can get another, less powerful for the other side.

That's really my only question. This will most likely be set up once I get another job, hopefully at a LFS

Feb 8, 2010
Very very nice guide. This is perfect. I have been a fresh water guy for 20 years now i selling my 55 fresh water tank and am getting ready to make use of my 29 gal nano Biocube Tank. I now have kids and need something simple and fun for them. The freshwater tank I am finally board of and just takes to much work and time. Of course i have had some of those fish for like 10 years (yes 10 years) and they have kinda grown on me so I will look for a nice home for them. The 55 gal tank is also costing me too much in electric as i figured out it runs me about 50-70 a month in electric costs due to the amount of Kwh it draws i am always over my limit and get chaged the next tier rate. I figured out that this tank will cost me like 10 a month for electric so the money I save in a year more than pays for the tank and the set up.

I am after a simple set up now. Just live rock, soem coral and a few fun fish, I must get the clowns as the kids love NEMO. I have been wondering how to set up my tank as i am new to the salt water world but not new to the fish world. I used to have a 240 gal fresh water tank. Now I need simple and easy. This guide is a great start and I will use it to start my tank.

Thanks for all the hard work you put in it.



Elite Fish
Sep 22, 2009
Northern NJ
Yes, A great Guide! I just started on one of these myself a little while ago, and am still in the cycling stage :) What's odd is that after 6 days now there is no hint of ammonia or nitrite and I'm getting 10ppm nitrates in the tank...I can see dangling die off from the rocks and the water smells of stale coffee but why am I not seeing any Ammonia/NO2? Don't know if I got cured or uncured live rock but as you said in the guide, I'll give this thing 14 days to show me some ammo/NO2 ;)

Sep 10, 2010
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.
  • 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 Fish Information Database -

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.
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.