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Discus Fish Size Guide (How Big Do Discus Get?)

Discus Fish Size Guide (How Big Do Discus Get?)

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This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

If you’ve ever seen discus fish in a friend’s fish tank before, you know that they’re absolutely gorgeous. They’re some of the most well-loved fish that you can buy due to how pretty they are.

You’ll certainly love looking at these fish if you choose to buy some. However, you might be worried about how big they will get.

Often, people recommend getting rather large aquariums when you plan to purchase discus fish. Do these fish grow to be rather large?

Keep reading to learn about discus fish sizes and what you can expect. It’ll make it easier to plan ahead so you can have everything go smoothly in your fish tank.

How Big Do Discus Fish Get?

The exact size of discus fish will differ based on the type that you buy. Some discus fish grow to be a bit larger while others will be a bit smaller.

However, an average discus fish is going to grow to be around nine inches long in captivity. These fish grow to be quite big and you’re supposed to keep them in tanks that are more than big enough for them.

You should expect most discus fish to reach at least seven inches in length in captivity. So long as they’re kept in warm conditions and cared for well they can grow to be large.

Some fish are even said to grow to be as large as twelve inches long. So you should do a bit of research about the specific discus fish that you’re interested in.

You should know that there aren’t discus fish out there that are radically larger or smaller. Discus fish generally grow to be around the same size even if there are slight differences.

This is why it isn’t always easy to find specific size information about the different variants. When looking up which discus fish types there are you will find most sources focusing on how the fish look.

They don’t give information about the size and instead focus on the generally accepted information about discus fish. There is some variance based on which type of fish you buy, but there isn’t a lot of information out there about specific sizes.

The best thing you can do is rely on the general information for these fish. Know that discus fish can grow to be large and don’t expect a fish to be smaller than seven inches long at maximum growth.

What Is the Largest Discus Fish?

The largest discus fish that people have seen in aquariums grow to be up to twelve inches long. These fish are cared for optimally and live for the maximum lifespan of the fish.

Understand that it isn’t necessarily typical for discus fish to grow to be twelve inches long. Most fish will never exceed nine inches long.

How Fast Do Discus Fish Grow?

You’ll find that discus fish grow at a decent rate so long as they’re being fed well and kept in an appropriate environment. Discus fish fry will grow to be two inches long in about two months.

By the time the fish is four months old, it should be three inches long. At six months old, the fish will be four inches long.

The growth rate slows a bit at this point. When the fish reaches nine months old it’ll only be around four and a half inches long.

Then by the time the fish is a year old it’ll be around five and a half inches long. At two years old, an average discus fish will be at least six and a half inches long.

It can take several more years for the fish to reach nine inches long. How fast this will occur depends on the quality of care that the fish receives.

How to Grow Discus Fish Faster

Growing discus fish faster is simply about caring for them well. These fish won’t grow as fast as they should if they’re living in a cramped environment.

You shouldn’t be keeping discus fish in tanks that are too small. Make sure that you’re using a 75-gallon fish tank or something larger.

Discus fish are schooling fish that need to be kept with others of their kind. You’re meant to keep a minimum of three to five discus fish in the same tank.

Many enthusiasts say that going with six fish or more is better. So if you want optimal results you’ll want six or more discus fish in a very large tank.

You’ll likely need a tank that exceeds 100 gallons of space to have the best results. Then you’ll need to focus on maintaining pristine water quality.

Water quality plays a big role in the health of these fish. You need to do regular tank maintenance and you must do multiple water changes per week.

Test the water regularly to ensure that the parameters are exactly where they need to be. This will give the fish an ideal environment to grow.

You also need to feed the fish the right types of food. Ensure that you’re giving the fish discus granules that meet their nutritional requirements.

Also, supplement this by feeding the fish live protein-rich foods from time to time. If you focus on doing this you’ll give the fish a great chance to grow to the maximum size at a decent growth rate.

What Are Some Small Discus Fish?

There aren’t really any discus fish that stay small. Discus fish grow to be quite large.

If the fish are kept in smaller tanks you might stunt their growth a bit. Even so, it’s unlikely that a discus fish would be smaller than six inches long after several years of growth.

So if you don’t have room for a larger tank it’s not wise to buy discus fish. You should go with some other type of fish that is closer to the size that you need.

Not everyone has room for discus fish in their home aquariums. These fish require large tanks and they also require a lot of work on your part.

Be honest about whether you’re ready to take on the responsibility. You can always put things off until your situation changes and you have more space for a big fish tank.

What Is the Smallest Discus Fish?

Generally, all discus fish are going to grow to be at least six or seven inches long as long as they don’t die early. Some discus fish might experience stunted growth due to many factors, though.

For example, discus fish that aren’t fed properly might have stunted growth. Also, discus fish that are kept in small tanks might not grow to their full size.

So it’s not a situation where there are dwarf discus fish that you can purchase from the pet store. These fish are simply large and grow to be quite large over the course of several years.

Juvenile discus fish will be under five inches long for quite some time, but by the time a discus fish is one year of age, it’ll likely be around five and a half inches long. Some make the mistake of buying young discus fish without knowing how large they will get.

Are Discus Fish Right for You?

You shouldn’t buy discus fish unless you think you’re ready for them. Know that these fish aren’t beginner-friendly.

Unlike many other popular fish, discus fish are finicky. They can die rather easily when you don’t take care of tank maintenance properly.

Many discus fish owners wind up losing fish due to poor water quality. Missing a few water changes or not using a good enough filter can easily cause you to lose fish.

You need to do multiple water changes per week when caring for discus fish. Also, you must clean the tank and make sure that all of their needs are being met.

These fish are needy and that might intimidate you a little bit. Raising these fish can be a positive experience, but it can also be a difficult one depending on how much time you have.

If you’re not someone who wishes to put a lot of effort into aquarium maintenance it’s best to avoid discus fish. There are much easier fish that you can purchase.

For instance, angelfish are hardy and beginner-friendly. You might wish to go with an easier type of fish that is still pretty enough to be enjoyed.

Don’t let this information deter you if you have your heart set on discus fish, though. You can indeed have a fantastic time with them so long as you’re ready to meet their care needs.

Final Thoughts

Now you know that discus fish grow to be quite large. Some of them can reach nine inches in length and there have even been discus fish that are twelve inches long.

Since these fish are big you’re going to need large fish tanks for them. It’s common for people to use 75-gallon fish tanks or larger options.

They might not be the most practical fish to own for most people. Discus fish are slightly tough to care for and they take up a lot of space in your home.

You must make sure that you’re committed before choosing to buy them. Otherwise, you might not have a good time.

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