20 Gallon Fish Tank Goldfish: Keeping How Many Of Each Type

You intend to set up a 20 gallon fish tank goldfish and don’t know how many goldfish should be kept? This article is for you.

There is nothing more fascinating than having a tank full of goldfish as a pet, and anyone who has ever had the pleasure of having them knows what a tremendously therapeutic experience this can be. If you are brand new to fish ownership, chances are that you will have a multitude of questions related to housing and care, which is perfectly normal. One of the questions we most commonly hear is can they keep goldfish in a 20-gallon fish tank. In this article, we will answer all your questions about the 20 gallon fish tank goldfish.

How Many Goldfish In A 20-gallon Tank?

Keeping fish in the tank can be made simple if you follow a simple rule. One-inch fish per one-gallon tank. According to this rule, a 20-gallon tank is large enough to house twenty small goldfish. 

In any case, you must keep in mind that it is not advisable to keep that many goldfish in such a small space. There is a high probability that you will face issues with ammonia and nitrite build-up because the bio-load will be so great that the filter won’t be able to handle it.

When determining how many goldfish you can keep in a tank, there are many factors to consider. To determine the correct number of goldfish for the tank size of 20 gallons, you must also take into account the fish size and the type of fish. 

To ensure your goldfish’s health and wellbeing, you need to ensure that you provide them with sufficient space so that they can swim freely.

Based On Goldfish Types: How Many Goldfish Should Be Kept? 

Common goldfish:

In a 20-gallon tank, you can keep two common goldfish. The common goldfish needs a lot of space. The growth of the goldfish is one of the main reasons for this. The goldfish grows fast, and it can grow up to 2 feet in length. This is the reason why two common goldfish will suffice in a tank of 20 gallons.

Fancy goldfish:

You can keep two common goldfish in a 20-gallon tank
You can keep two common goldfish in a 20-gallon tank

If they are one or two inches long, you can keep five to ten fancy goldfish. However, in the case you are planning to grow the fish quickly, you should not keep more than one or two goldfish in a 20-gallon aquarium. 

I have heard the rule of thumb that it takes 20 gallons to keep a fancy goldfish from several people, so it would seem that you could keep one.

Comet goldfish:

 You should only keep one comet goldfish in a 20-gallon tank
You should only keep one comet goldfish in a 20-gallon tank

More than five to ten small goldfish can be kept in a 20-gallon tank. However, if you want to keep a comet goldfish in a 20-gallon tank, you should only keep one comet goldfish. Comet goldfish can grow rapidly and reach 12 inches in length when they become adults.

Fantail goldfish:

You are only allowed to keep two small fantail goldfish in a 20-gallon tank
You are only allowed to keep two small fantail goldfish in a 20-gallon tank

If you have a 20-gallon tank, you are only allowed to keep two small fantail goldfish in it. That would be a better space for them to swim freely.

If you put too many of them together, your tank will be overcrowded, and they won’t be able to find enough space to live happily.

Video About 20 Gallon Fish Tank Goldfish Setup


How long do goldfish live in a 20-gallon tank?

The life expectancy of goldfish is quite long. They can survive without water for up to three hours. Therefore, with a 20-gallon tank, they will surely survive more than years.
If you want to extend the lifespan of the goldfish, you should keep it in a pond. They can live for 20 years in a large pond.

Is 10 gallons enough for a goldfish?

If you are asking about a 10-gallon tank, I would say that it is only suitable for one or two baby goldfish. Once your fish outgrow the tank, you need to consider at least 20 gallons of space for each additional fish.

Can goldfish live in a bowl?

Goldfish can live a long, happy life in a bowl that holds from three to five gallons. But ideally, an adult goldfish should be kept in a bowl that holds at least ten gallons. This will allow for leeway with water changes when life becomes busy and ensure the quality of the water remains high. 


So, keeping a 20-gallon fish tank goldfish is possible. You have to decide how many goldfish you should keep, ensuring your fish can stay happy and healthy. 

To determine how many goldfish you should keep in a 20-gallon tank, you should consider many factors, such as fish size and fish type. Hopefully, our article has clarified this issue for you. 

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