How Many Fish Can You Keep In A Fish Tank?
Many times when starting a tank, the most popular and very important question is: How many fish can I keep in my aquarium? Of course there are many problems with over-stocking an aquarium such as insufficient oxygen, lack of space etc. Most of our exotic fish will take a lot of punishment before coming to the surface to whisper their complaints by breathing atmospheric air. They can be overcrowded without any such demonstration.
Many times the aquarium is in beautiful condition but the fish do not grow. This brings out the fact that the fish have neither enough “elbow room” nor oxygen and sometimes underfed. The rule of thumb I have heard many times is “1 inch of fish to 1 Gallon of water”. This, however, is only a rule of thumb, and many times it is hard to apply it to a specific fish.
For example, let’s compare a 3″ neon tetra, 3″ discus, 3″ tiger barb, 3″ betta, and 3″ cichlid. Each fish has different requirements. A 3″ discus would not be able to live in a tank suitable for a 3″ betta because of space. Even a 3″ neon and a 3″ betta have different requirements because the betta is a labyrinth fish. And if we take it even further, a 3″ barb and a 3″ neon need slightly different requirements as barbs are taller in body and neons slimmer. I could name many more examples but I think that you can see my point. Each fish has its own requirements.
The following then can be used to determine the number of fish in an aquarium. The first step is determining the surface area of the tank. Keep in mind when using the size of fish; it has to be the maximum growth the fish will reach.
For fish the size of grown Guppies, 3 square inches of air surface per fish. That is to say, an aquarium 9 x 20 inches, with an air surface of 180 square inches, can safely support 50 grown guppies, giving each over 3 inches. Other exotics the same size rate a bit more, as Guppies have great powers of standing overcrowding.
Labyrinth fish (Bettas, Paradise, Gouramies) need about half the amount of air surface calculated per fish of the same size.
Swordtails, large Platies, etc., need about 8 square inches per fish (4 x 2 inches, or equivalent).
Medium Barbs, 3.5 inches in size, and other fish of equal weight should have 20 square inches per fish (4 x 5 inches, or equivalent).
Large Barbs and Cichlids of 5-inch length require a minimum of 54 inches per fish (6 x 9 inches, or equivalent).
These are minimum requirements, not taking into account plants or aeration and at a temperature of about 74 degrees. For health, growth and first class conditions, the air-surface per fish should be doubled or even tripled. A large aquarium can support a little higher percentage of fish in proportion to its size than a small one.
By: Ron Reisdorf
**Data taken from ‘Exotic Aquarium Fishes’, 19th Edition Revised by Dr. William T. Innes
I was wondering if I have over crowded my 47 gallon, tall tank? I have 3 pretty big Angelfish, 1 Ram and 1 tiny shark with red fins. If so, which ones need to be moved to a larger tank? Thanks.
i’d suggest moving all of them to a bigger tank.
you can’t ever have a big enough tank. but have you joined our forum? you can ask your question there and our helpful members can assist you.
http://www.myfishtank.net/forum
I’m pretty sure my tank is overcrowded. My boyfriend continually keeps adding fish and I keep telling him that there are two many. Here is what we have we have 3 neon tetra, 4 African dwarf frogs, 2 Serpae tetra, 3 small dwarf gourami,2 bala sharks, 2 fancy guppies, 2 buenos aires tetra, 2 black skirted tetra, 1 dojo loach. Let me just say all of the fish are very small our largest fish are only an inch and a half to two inches in length. Which there are 6 of those that are in that size range. Should we purchase a larger tank? How large of a tank should we purchase?
I forgot about two little guys he just added hatchet fish.