Tank Sizes For Goldfish: Goldfish Tank Size Guide

Goldfish Tank Sizes

Goldfish is a colorful and fine fish to keep in the home aquarium, many people love to keep this kind of fish because of their golden color which is very magnificent and highly beautiful. There is a popular questions about the size of tank this fish could be comfortably kept in, if they could be kept in a 40 gallon etc and how many of them should be kept in such tanks. In this article, we will) enlighten you on the number of goldfish that you can be able to keep in different tank sizes.

How many Goldfish should be in a 40 gallon tank? Only 2 goldfish could be comfortably kept in a 40 gallon tank.

Although goldfish that are raised in captivity are not so huge in size, infact they are so small and could hardly get up to 3 inches in size.

So aquarium breed goldfish are normally small, unlike those that live in the wild which could grow up to 15 inches in size.

Related: Clownfish tank sizes

So you can see that those of them in the wild are quiet different from those in captivity, interms of size, but despite being small in size, those aquarium goldfish still requires enough space too inorder to thrive.

The minimum amount of tank space a single goldfish needs to thrive is 20 gallon.

You might be surprised that such a small fish could need such amount of space in order to be alright, well, it’s their nature.

So back to your question, if you have only a 40 gallon tank or 45, as the case may be, or you want to purchase, then have it in mind that you can only be able to stock just a pair of goldfish in it. (2 goldfish)

This is because they need enough space in order to swim about and be healthy.

How Many Goldfish can I put in a 37 Gallon Tank?

Having known the minimum tank size a single goldfish could be able to occupy and live comfortably, you might begin to wonder, how many of them should you put in a 37 gallon tank.

How many Goldfish can I put in a 37 gallon tank? A 37 gallon tank could only contain 1-2 goldfish, depending on their sizes.

If you’re planning to have a group of goldfish in your aquarium, then a 30-37 gallon is very small, as it can comfortably contain only one fish.

Related: Can 2 Goldfish comfortably live in a 1 gallon tank?

So if your tank is 30 gallon, then know it that only one goldfish will survive, unless they are still juvenile and haven’t matured yet.

So 30 to 37 gallon tank is too small and could barely contain up to 2 adult goldfish.

What Size Tank Do I Need For 7 Goldfish?

Some goldfish are small and some are big. If you have 7 of them or you want to get 7, then you will be wondering how many gallons of a tank you will need to keep them comfortable and healthy.

What size tank do I need for 7 goldfish? To comfortably keep 7 matured goldfish in a tank, you need a tank size of not less than 140 gallon.

This is base on the fact that each of this fish needs a tank size of 20 gallon or more to live comfortably.

Although sometimes their size is insignificant as some can only get up to 3 inches, but some can still grow up to 15 inches and a bit more, so to be on the safe side, you should budget for a more tank space because you might not know how your fish will grow as time goes on.

Apart from how large they might grow, even those with small sizes still need a lot of space too, so it’s almost the same, and your budget should be huge when it comes to tank size, depending on how many you want to keep.


Your pet is your friend and should be treated as such, so making them feel comfortable should be your priority.

Get your pets a more comfortable and large environment, so that they will feel as if they’re still in the wild and will feel healthy and active too.

So tank size matters a lot to Goldfish, and you should provide it for them and never overstock them.