How many fish can I put in a 3 gallon tank?

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by Jason Matthews


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So, you have bought a 3 gallon tank and you can’t wait to put some fish in it to enjoy the beautiful spectacle of nature, however, you are questioning yourself about the number of fishes that you can put in such a tiny tank? Well, don’t worry, we are here to help.

Obviously, there is no precise answer to a question like that, as freshwater fish come in many different species and each of these has different dimensions. Speaking in general, a 3 gallon tank, given its little dimensions, can’t host much fish. You will also have to choose between a bigger fish, but alone, or many (not too many), but small.

Size and type of the fish

If you go with a bigger one it shouldn’t be any bigger than 2 inches as an adult, otherwise, it could have growth problems: it would remain small, atrophied and weak. This would lead to unnecessary stress and, obviously, premature death of the fish. It is also important to understand if the fish that you chose can live alone, as usually fish live in schools. A lack of tank mates of the same species would cause the fish to suffer from loneliness and stress, leading, once again, to premature death.

Related article: What fish should put in a 3 gallon tank

On the other hand, if you choose to host small fish in your 3 gallon tank, you should be sure that each fish won’t grow above 1 inch long, otherwise, the tank would become overcrowded, causing stress and instability of the water parameters (high levels of nitrites and nitrates because of the heavy organic load).

Another important factor to keep in mind when choosing much fish of the same species is the fact that they could breed. Because of this, it’s important at first to understand if the species that you chose breeds in captivity, if the answer is yes then you would probably need to bring some of the new-born back to the shop to avoid overcrowding. Always ask the shop owner if he would accept them back in case!


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

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