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How Big Do Oscar Fish Get? (Plus Tips for Better Growth)

How Big Do Oscar Fish Get? (Plus Tips for Better Growth)

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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.

You’ve likely heard that Oscar fish are fairly big. It’s generally not a good idea to buy these fish if you don’t have room for a sizable aquarium in your home.

People love buying these fish because of how fun they are, though. They have some of the best personalities among popular pet fish options.

If you’re looking into buying Oscars for your fish tank, you likely want to know more about them. How big do these fish get on average?

Read on to learn about Oscar fish and how big they get. You’ll get the answers to many common questions that are related to this topic.

Having more knowledge about Oscars will help you to make good decisions for your fish tank. Once you’ve read everything, you can decide how you wish to proceed.

Oscar Fish Max Size

At maturity, Oscar fish are going to grow to be rather large. These huge cichlids have the potential to grow between twelve and fourteen inches long.

In captivity, it’s more common for the fish to grow to be twelve inches long. Sometimes Oscars will be slightly over eleven inches long in captivity, too.

Wild Oscar fish have an easier time reaching their maximum size potential. They live in large environments and it makes sense that they would get really big.

Oscar fish can get that big in captivity as well, but they often stay around twelve inches long. Of course, there are things that you can do to help your fish grow that you will learn about later.

Be aware of how big these fish can get. You must have room for these fish if you want to care for them properly.

They’re so large that they might not be practical for some fish tank owners. If you live in a small environment, you won’t want to buy these fish since it might create a burden.

Those who live in homes that have enough room will love Oscars, though. They’re truly remarkable fish that are so fun to observe.

Looking at how huge and impressive they are will never get old. They’ll certainly impress the guests that come over to look at your aquarium, too.

Biggest Oscar Fish

All Oscar fish have the potential to grow to be between twelve and fourteen inches long. It’s more common for Oscars to grow as large as possible in the wild.

Generally, they will grow to be around twelve inches long in a fish tank. There have been instances where Oscar fish have grown to be fourteen inches long in captivity, but this isn’t the norm.

There isn’t a specific type of Oscar fish that you can buy that’s considered to be the biggest. Oscars are all pretty much the same.

You’ll find Oscars being sold in stores under different names. It’s common to see albino Oscar fish, tiger Oscar fish, and various other types.

These aren’t truly different fish from a genetic perspective. They’re simply fish that have been selectively bred to have different colors and patterns.

They look really impressive, but they’re not different in terms of care requirements or maximum size potential. Now that you know this, it’s easier to focus on the general information below to solve all of your Oscar fish size queries.

Smallest Oscar Fish

As noted earlier, there aren’t really different types of Oscars from a genetic standpoint. They’re just variations that have been bred to have specific colors.

Therefore, all Oscars are going to grow to be around twelve inches in captivity. They have the potential to grow to be up to fourteen inches long in the wild.

These are large fish and there won’t be small versions of Oscars that you can buy from pet stores. If you buy a small Oscar fish, it’s a juvenile fish that simply hasn’t grown to its full size yet.

Those who are interested in smaller fish are better off buying different types of cichlids. These cichlids are big and require rather large fish tanks.

How to Tell Oscar Fish Age

Are you wondering how old the Oscar fish that you bought is currently? You can sort of approximate the age of the fish based on how large it is.

It takes between twelve and fifteen months for Oscars to reach four or five inches in length. It’s at this time that the fish will be sexually mature.

The fish won’t have reached their maximum growth potential yet, but you’ll know that your fish is at least one year old when it’s around this size. Other than this, it’s not really good to try to determine the age of the fish by how big it is.

You see, there are various factors that impact the growth rate of the fish. You’ll learn more about how to encourage Oscar fish growth later on.

Oscar Fish Growth Rate

How fast do Oscar fish grow? They don’t grow too fast at the beginning of their lives.

Many people say it takes juvenile Oscars a few months to grow to be one or two inches long. Eventually, the growth rate kicks up a notch, but many say they’re “late bloomers” as far as size goes.

After twelve months or so, the Oscar should reach four or five inches in length. At this size, the Oscar fish will finally be sexually mature, but it’ll still have a long way to go to reach full size.

Some Oscars will grow rather fast while others will grow slowly. It depends on factors such as the tank conditions, how much food you’re giving to the Oscar, and other things.

Oscar fish owners have noted that they’ve seen the fish grow as much as one inch per month. Not all fish will grow that fast, but it’s possible to have that type of growth rate.

In some cases, Oscars might reach the maximum size of twelve inches in just a bit over one year. Other Oscars might take two years to reach twelve inches in length.

Many have noted that Oscar fish growth seems to slow down once the fish reaches nine inches in length. So there could be times where your Oscar fish will have a less rapid growth rate.

Honestly, it’s hard to give a specific growth rate for these fish. So many factors play a role in how fast the fish will grow.

It might be better to focus on what you can do to encourage growth. If you do a good job, you can expect the fish to grow a bit faster than average.

How to Grow Oscar Fish Fast

So what can you do to make your Oscar fish grow faster? Are there certain methods that you can utilize?

There’s a lot that you can do to have a positive impact on Oscar fish growth. A lot of it involves doing the basics very well.

Caring for the fish to the best of your ability will make a difference. If you can focus on giving the fish excellent care, there’s a good chance that it will have a strong growth rate.

Keep reading to get information on things that can have an impact on the growth rate of the fish. This should allow you to change your approach to raising the fish if your goal is to help the Oscars reach full size fast.

The Tank Size Matters

Understand that the tank size matters a lot when caring for these fish. You really shouldn’t even be keeping these fish in your home if you don’t have room for a 100-gallon fish tank.

When caring for multiple Oscars, it’s like a good idea to buy a 150-gallon fish tank. You want the Oscar fish to have plenty of room to live and be happy.

The fish will have an easier time growing when they’re living in a large tank. It’s even best not to keep juvenile Oscars in a small tank when they’re young.

Experts recommend starting the Oscars out in a large tank to encourage maximum growth potential. This means keeping the fish in a 100-gallon aquarium from the beginning instead of something smaller such as a 50-gallon fish tank.

A smaller tank could negatively impact the growth rate of the fish. So try to get the biggest tank that you can (within reason) for your Oscar fish.

Having a large and impressive tank should be very satisfying. You’ll love having a good environment for your Oscar fish.

Do your best not to overcrowd the tank even if you buy a large one. It’s fine to put several fish in the tank, but you don’t want to go overboard.

Oscar fish get stressed when they live in crowded fish tanks. Stress can impact the growth rate and you don’t want that.

Do make room for hiding spots, rocks, little caves, and other things that your Oscars will appreciate. It’s fine to put other types of fish in the tank so long as they’re compatible with the Oscars, but don’t add more fish than you should.

Feed the Oscar Fish Very Well

You likely expected food to play a role in how well the Oscar fish will grow. Feeding the Oscars a high-quality diet will help them to grow big and strong.

This is also part of keeping the Oscars in great health. You want to make sure that you’re feeding them enough food and that you’re choosing the right types of food.

The daily food that you’ll be giving to Oscars are cichlid flakes and nutritional pellets. These foods are formulated to be perfect for large cichlids such as Oscars.

They give them the essential nutrients that they require to grow large. Your fish will eat this stuff up without question.

This isn’t the only type of food that you should be giving to the fish, though. Oscar fish are omnivores and that means that they eat many things.

In the wild, Oscars eat meaty foods as well as veggies. You’ll need to supplement the diet of the fish with various meaty treats.

It’s common for people to give Oscar fish live foods such as various types of worms, shrimp, and even small crustaceans. Some might even choose to give their Oscars feeder fish, but this isn’t a requirement.

Many people find it easier and less annoying to give the fish frozen or freeze-dried food. Freeze-dried shrimp and bloodworms can be great things to purchase from the pet store.

If you choose frozen food, thaw it out before giving it to the Oscars. This is less of a hassle than giving the fish live food, and it’s just as good for them.

You may also want to cut up veggies to give to your fish sometimes. Fruits can also be a good snack for your Oscars.

Feed them cut-up pieces of spinach, carrots, boiled peas, lettuce, and apples. Your fish will really wind up enjoying this a lot, but be sure to clean everything before giving it to the fish.

When it comes to feeding Oscars, you should know that juvenile fish need to eat more often. They like to eat three or four times per day.

It’s fine to feed mature Oscars two times per day. Try to stick to a feeding schedule so your Oscars can grow as fast as possible while remaining healthy.

Maintain Great Water Conditions

The conditions in the tank are something you must pay attention to. If you want your fish to stay healthy and grow strong, they need to live in a fish tank with good water quality.

To keep things safe for the fish, it’s important to monitor the conditions in the tank. This involves testing the water using pH balance testing kits.

You also need to maintain the right temperature in the aquarium. If things are in the right range for the fish, they’ll have an easier time growing and staying in good shape.

You want the pH balance of the water to be between 6.0 and 8.0. The best number to shoot for is 7.2.

Keep the temperature of the water between 74 degrees Fahrenheit and 81 degrees Fahrenheit. Ensure that you’re using a reliable heater that can keep the tank warm.

If anything is ever off, you should be able to fix the pH balance using chemicals. Maintaining the right balance is easier when you focus on tank maintenance.

Oscar fish are very messy eaters and they’re going to make the water dirty. Having a good filter can help to keep the tank clean.

Even when you own a good filter, it’s still necessary to clean the tank. You should do regular tank maintenance cleaning sessions.

It’s also wise to do weekly water changes. Many enthusiasts say that weekly water changes of 30% will be good for these fish.

There are some who do two water changes per week. This isn’t necessary for the health of the fish, but anecdotal evidence suggests that more frequent water changes might have a positive impact on the growth rate of Oscars.

Simply paying close attention to the tank and maintaining high water quality will help a lot. If you do your best to keep the water quality where it needs to be, your fish will experience far fewer health issues throughout their lives.

Avoid Stressing the Fish

Don’t stress the fish or it will make them have growth issues. This means you should avoid putting them in bad situations.

If you put them in a community tank, be sure to pick out appropriate tank mates. Putting the Oscars in a tank with fish that will try to bully them will cause them significant stress.

Not feeding the fish often enough can cause them stress. So will improper conditions in the tank.

Be mindful of things that can cause fish to experience stress. Do your best to keep the fish in a good environment where they can live happily and they’ll grow as fast as they can.

Genetics Can Play a Role

Genetics plays a role in how fast fish grow, too. If the fish came from a line of fish that were a bit on the small side, they might not grow as large as others.

For instance, some Oscar fish only grow to be slightly over eleven inches in captivity. If your fish doesn’t seem to be able to make it to twelve inches, it could simply be related to the genetics of the fish.

Final Thoughts

You’ve learned everything that you need to know about Oscar fish and how big they can get. These are huge fish that can grow to be twelve inches long in fish tanks.

Sometimes the fish might be a little smaller, but they regularly get to twelve inches long in home aquariums. Wild Oscar fish can grow to be fourteen inches long.

If you give your fish enough food and take care of the fish tank well, it’ll help it to grow fast. These fish often don’t grow super fast in the early stages of life, but they will start growing faster as they get older.

Look after your fish and you should be able to look forward to them getting big. Be sure to give them a large fish tank where they’ll have the room to grow.

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