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What Size Tank For 2 Goldfish? What You Need To Know

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By Lindsey Stanton


When it comes to keeping fish at home, one of the most common fish that people have is the goldfish. This is especially true for children and beginners who want or need something easy to take care of.

Of course, you do need to meet certain requirements for your fish to be happy and healthy. One of these requirements is the tank, or more specifically the size of the tank. So, what size tank is necessary for two goldfish? And what about just a single goldfish? Read on below to find out.

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How Many Goldfish Per Liter?

As you will be able to tell from the section below, a normal common goldfish requires at least 30 gallons of tank space. 30 gallons is approximately 120 liters. Therefore, you can have one goldfish for every 120 liters of water in the tank. Each additional common goldfish past the first one will require a minimum of 12 extra gallons of tank space.

Image Credit: dien, Shutterstock

In other words, two common goldfish need 42 gallons of space at a very minimum. That translates to roughly 168 liters of water. So, for 168 liters of water, you can have two goldfish. If you want to have three, add an extra 12 gallons or 48 liters to that. Thus, three goldfish would require roughly 216 liters of tank space. Please remember that this is the absolute minimum (also don’t forget to add safe plants, more on those here).

What Size Tank Is Needed For 2 Goldfish?

One important thing to know is that there are two main types of goldfish commonly housed in home aquariums. There are the common goldfish and the fancy goldfish, both of which require slightly different tank sizes.

Keep in mind that both of these types of goldfish need a good amount of space. What you also need to remember is that here we will be talking about the minimum tank size for these fish, as well as the recommended tank size to make sure that they are comfortable.

If you're new to the world of goldfish or are an experienced goldfish keeper that loves to learn more, we recommend you check out our best-selling book, The Truth About Goldfish, on Amazon.

From diagnosing illnesses and providing correct treatments to ensuring your goldies are happy with their setup and your maintenance, this book brings our blog to life in color and will help you to be the best goldfishkeeper you can be. 

NOTE: There are actually 15 different types of goldfish! We have covered them all here.

The Common Goldfish

goldfish in tank
Image Credit: Unsplash

First off is the common goldfish. This kind of goldfish requires a tank that is at least 4 feet long and 30 gallons in volume. Now, this is the absolute minimum. If you want your common goldfish to be very happy in its home, a 35 or even a 40-gallon tank that is between 4.5 and 5 feet long is best. Now, in terms of two common goldfish, you will want to have a tank that is at least 42 gallons large.

The minimum for a single common goldfish is 30 gallons, with our recommendation being 40 gallons. However, for each additional goldfish, you will need an additional 12 gallons of water. Now, once again, this is the absolute minimum.

If you really want your common goldfish to be comfortable, you will need an extra 20 gallons of volume for each additional fish past 1. Therefore, ideally speaking, 2 goldfish should have between 50 and 60 gallons worth of water volume available to them.

If you need help looking after your Goldfish, then check out this article for a full beginners guide.

The Fancy Goldfish

veiltail goldfish
Image Credit: Pixy

The other type of goldfish that many people have at home, a slightly more expensive kind, is the fancy goldfish. As opposed to what you might think due to this animal’s name, it is a bit smaller and requires slightly less space than the common version.

For a fancy goldfish, a minimum tank size of 3 feet in length and a volume of 20 gallons is required. Once again, this is the minimum. If you want your fish to be very comfortable and happy, you should go with a 3.5-long tank that can hold at least 25 gallons of water.

Also, for each additional fancy goldfish after the first one, you need to increase the tank size by a minimum of 10 gallons. Seeing as 10 gallons is the minimum, we personally would recommend an extra 15 gallons of space after each fish past the first one.

Therefore, to make your fancy goldfish really happy, two of these animals should have around 35 to 40 gallons of tank space, with a tank that is between 3.5 and 4 feet in length.

If you need some goldfish food and feeding help then we have covered a helpful article here that you might like.

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Many people seem to think that goldfish can be kept in bowls, and really small bowls at that. This is a common misconception and we honestly are not all that sure where it comes from. However, the bottom line is that goldfish actually need quite a bit of space as you can see. Now, they are not all that hard to take care of, but they do need a good deal of room to feel at home.

Featured Image Credit: hxdbzxy, Shutterstock

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