How many fish can you have in a tank?


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All Answers (6)


The old school answer would be 1" of fish per 1 gallon of water. That can lead to overcrowding and excessive waste products in your tank depending on the nature and requirements of your specific fish; but it can be a rough starting point.

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Marietta H.

I was told the general rule is that you can have one inch of fish per gallon of water that the tank holds. But you still need to consider the types of fish and whether any are aggressive when buying fish....Read More

Garry V.

It depends on the size of the fish and the size of your tank, of course. Some aquarium enthusiasts will tell you that you can accommodate one inch of fish with every gallon of water. I'd suggest you also consider how many plants and decorations, etc. you're using. Your fish should have room to swim....Read More


well, i know you can fit about 378 goldfish in a bathtub. Next time I want to see how many I can fit in a hot tub. I will keep you updated.

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It depends on the size of the tank, the kind of fish and how good the system is. I once had 8 tanks, 3 salt water and 1 that was a brine water, for fish that like that environment. Don't overfeed as the spoiled food adds ammonia to the tank. Have a good filter and do regular water changes. Don't introduce a lot of fish at once. You can buy testing equipment to be sure your water is healthy. Small fish that like to school are not included in the 1 fish per gallon rule. Some fish like water plants and fake grass is good for hiding places. Do use a gravel cleaner often to keep the water clear . I had a lot of fish and enjoyed them a lot. I had a moray eel in a 10 gallon by himself. I fed him kibbles and bits on a stick with a nail in the end so he got the food and not my finger. He hid a lot but when he saw the stick, he came running. Become well educated about fish before you go for the big deals and there are good books to help you do it. Don't scrimp on equipment; it pays to buy the best you can. Don't put a tank near a window; the light will encourage algae and it's a nuisance. Have fun! It's a peace place to be, watching your tank.

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Coal M.

One inch of fish per gallon of water. Factor in types of fish, not all get along. Allow for proper space with growth. Depends on filtration also. I use a filter with biological and mechanical that does 5 x the water volume per hour

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