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What Size Tank Do You Need For two Goldfish?

Goldfish are some of the most manageable pets you can have. If you have only recently decided to be a fish owner, they’re the perfect fish for beginners.

They’re amusing to watch, easy to care for, and can live for several years if you give them the right environment to thrive in.

It’s always preferred to purchase more than one goldfish because they cannot stay healthy on their own. They are social creatures and need other fish to stay happy and active.

As a beginner, you can invest in two goldfish and work up from there. On average, you need a 50-60-gallon tank for two goldfish.

What’s the Smallest Sized Tank You Can Keep a Goldfish in?

If you’re facing issues such as a lack of space in your house or apartment, you probably won’t be able to invest in a large tank.

However, as tempting as it may be to get a smaller tank—it isn’t very healthy for your goldfish.

You should strictly avoid keeping goldfish in a fishbowl. As traditional as it may seem, goldfish are actually extremely uncomfortable in these small bowls.

Not only do they suffer from a cramped space to swim in, but they’re also more likely to fall sick and live shorter lives.

This is because goldfish produce much more waste than other kinds of fish. In a limited amount of water, the tank is likely to become polluted quicker and lead to an unhealthy environment.

A fishbowl has a significantly higher rate of becoming polluted in a shorter amount of time.

So, what’s the smallest viable option you can go for? The minimum size you could have is a 10-gallon tank, which would be just enough for one goldfish.

And if you want two goldfish, then a 20-gallon tank could pass as acceptable.

To make this environment livable for your fish, you’ll have to regularly clean out the aquarium as many as two times a week.

You’ll also have to invest in a high-quality filter to ensure that the tank stays as clean as possible.

What Happens When You Keep Goldfish in a Small Tank?

Contrary to what many people believe, goldfish do not only grow to the size of the tank they’re in. They can actually grow quite large, up to 14 inches in the wild.

This is because they’re given the freedom to grow without the limitations of a small tank.

When you keep a goldfish in a small tank, you’re actually stopping it from reaching its full potential length and size.

The larger your tank, the more chances your goldfish have of living a longer life and growing to their full size.

Even if you do start off with a smaller tank while your fish are young, you should be prepared to upgrade to a larger tank once they get older.

Depending on the breed of goldfish you have, you will have to invest in a tank that’s anywhere from 50 to 60 gallons.

Instead of focusing on how big your fish currently are, you should be getting a tank based on how big your fish can get.

The average fancy goldfish can only grow 6 inches at most in a small tank, and a common goldfish can grow to 8 inches—far from its potential length.

Goldfish also tend to need more space to swim around because they are active creatures. That’s why you can never go wrong with a tank that’s too big.

The more space a tank has, the more goldfish you can keep, which provides an opportunity for socialization and keeps your fish healthier and free of disease.

Do Different Breeds of GoldFish Need Different Sized Tanks?

Yes, because different breeds of goldfish grow to different sizes. A common goldfish will usually grow to be much larger than a fancy goldfish.

In the amount of space you have for two fancy goldfish, for example, you can only keep one common goldfish.

If you have two common goldfish, a tank of 50-60 is the ideal size. Try to aim for a tank with more water surface area than depth, because goldfish prefer longer tanks.

For two fancy goldfish, however, a 30-gallon tank can work.

The rule of thumb is to have 1 gallon of water for every inch of fish. Because goldfish are more active and pollute more, it’s safer to assume 2 gallons of water for every inch.

Your first fancy goldfish needs 20 gallons of water. When you add a second to the tank, you need to add on 10 more gallons. If you add a third, you need at least 40 gallons.

For common goldfish, your first fish needs 30 gallons of water as the starting point. When you add a second, you need to add 20 more gallons.

And if you want three common goldfish, you need at least 50-60 gallons.

These are the numbers you should keep in mind if you are prioritizing your fish’s health as opposed to the best-sized tank for your living space.

As mentioned above, fish can and do live in smaller sized tanks but are often unhappy and do not live as many years.

How Big Should a Goldfish Tank Be?

Once you’ve determined how many fish and what breed of goldfish you want, it’s time to move on to the tank size.

The volume of a tank is not all that matters when it comes to goldfish. They prefer taking leisurely swims through the length of a tank—so the longer your tank, the better.

On average, a tank for one common or comet goldfish should be 4 feet in length. For a fancy goldfish, the average tank length should be 3 feet.

If you plan on adding more fish, a longer tank will be a smarter choice. However, these lengths are acceptable for two goldfish, based on their breed.

In fact, if you can get your hands on an L-shaped tank, it would be a great choice for your goldfish because it provides more space to swim.

How Big Can Goldfish Get?

The average fancy fish can grow up to 8 inches when provided with a large tank. And a common goldfish can grow up to a foot or more!

Not only have people been misinformed of the size goldfish can grow to—they are also unaware of how many years goldfish can live.

The average goldfish can live up to 40 years. Considering how most pet fish do not make it past a few years, it is evident that goldfish are not provided with the environment they need to live out their full lives.

They usually die early from poor tank conditions, lack of space, and loneliness.

What Other Things You Should Consider Before Getting a Tank?

Some important things to remember before you invest in a tank and goldfish are breed and swimming preferences.

Fancy goldfish are smaller than common goldfish, which means that placing the two breeds together isn’t always a good idea.

The common goldfish are likely to eat their feed and leave the fancy goldfish without the nutrition they need.

Common goldfish can also attack or become bothersome to fancies, so it’s better to stick to one breed of goldfish in a tank.

They’re also much happier when they’re with other fish of their own breed. Common goldfish also swim faster, so a longer tank works best for them.

Goldfish, as mentioned above, produce much more waste than other fish. This means you need a stronger filter in the tank. You also don’t need to get a water heater because goldfish are comfortable in the water around 50-75 F.

When deciding on the size of the tank, you need to keep in mind that accessories will reduce the space the fish have to swim.

Make sure you consider the volume taken up by different tank decorations before you decide on a size. Although these accessories are important, too many of them, especially if they’re too big, can make your tank congested and stuffy.

You should generally go for fake plants and small accessories that stay near the bottom of the tank.

Goldfish are known for destroying any real plants in the aquarium—so soft artificial plants are the best option. Accessories are also important for giving goldfish an area to spawn, hide, and play.

Final Words

There are numerous myths that surround the proper care and treatment that goldfish need. They have the potential to live for many years and grow to significant sizes.

They’re not meant to be limited by a small tank—because it’s detrimental to their health. They’re also very social creatures and should always be bought in pairs, at the least.

With the right guidelines about maintaining pet goldfish, you should ideally have them around for several decades.

If you start off with a tank that suits their maximum potential size, you won’t even have to worry about upgrading to a larger one in the future.

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