What Do Oscar Fish Like In Their Tank? (A Complete Guide)

If you are planning to keep Oscar fish in your tank. Or if you already have Oscar fish but wondering, what do Oscar fish like in their tank then you are in the right place.

In this guide, I will tell you everything Oscar fish like in their tank.

What Do Oscar Fish Like In Their Tank (A Complete Guide) image

So, what do Oscar fish like in their tank?

In the tank, Oscar fish like temperatures between 71 to 84° Fahrenheit, pH between 6 to 8, and hardness between 5 to 20 dH.

Besides, Oscar fish like a larger tank. And you can add plants, tankmates and decorations to emulate their natural habitat.

Basically, Oscar fish like the ideal environment that will help them to grow and live a stress-free in the tank.

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What is the ideal environment for Oscar fish?

Obviously, the natural habitat of Oscar fish is the ideal environment for them.

So, you have to emulate the same environment in your fish tank to create the ideal environment for your Oscar fish.

How to create an ideal environment for Oscar fish in your tank?

There are several things you can do to create the ideal environment for your Oscar in your tank. So that your Oscar will grow and thrive in your fish tank.

Tank size

Oscar fish can grow pretty large and it grows very rapidly.

When you get a baby Oscar fish it looks cute little fish but Oscar fish can grow at a very fast rate. It can grow at a rate of  1 inch per month. And usually, in a fish tank, it grows up to 12 inches.

But it can grow larger than that if you take good care of it and provide it the ideal environment.

That’s why tank size is one of the most important things when it comes to creating the ideal environment for Oscar fish.

So, what is the ideal tank size for Oscar fish?

As Oscar fish grow pretty large, it requires a larger tank.

The ideal tank size for a single Oscar fish is 55 gallons.

You can put baby Oscar fish in a smaller tank. But, as mentioned earlier, Oscar fish grows very fast so eventually, you will have to put it in a larger tank.

You can even put a large Oscar fish in a relatively small tank say 30-40 gallons. But then you will have to do water changes multiple times per week and that can be a pain.

As you can see in the above video this guy or gal has kept multiple Oscars with other fish in a relatively very small tank. 

With a 55-gallon tank doing water change once a week is sufficient. And it will also provide a lot of space to your Oscar fish to swim around and create its territory in the tank.

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Water condition

Maintaining an ideal water condition is paramount when it comes to the proper growth and development of your Oscar fish.


Oscar fish cannot regulate their body temperature and so they are dependent on the temperature of the water of your tank to maintain their body temperature.

Ideally, your tanks should have water temperature anywhere between 74 to 81° Fahrenheit.

Oscar fish cannot survive in cooler water for a long time. 

If your tank has cooler water then the easiest and simplest way to raise the temperature of the water is by introducing a heater in your tank.

On the other hand, high water temperature is also bad for the health of your Oscar fish.

If your tank has a high water temperature then you can use these ways to reduce the temperature in your tank.


The ideal pH range for Oscar fish is between 6 to 8. Usually, pH will be within the ideal range if you’re using normal tap water in your fish tank.


The ideal water hardness tolerance range of Oscar fish is between 5 to 20 dH. Usually, hardness will be within the ideal range if you’re using normal tap water in your fish tank.


High ammonia levels can be deadly for your Oscar fish. So keeping the ammonia levels under control is very important for happy and healthy Oscar fish.

Ideally, your tanks should not contain any ammonia.

There are bacteria called beneficial bacteria in the aquarium that help to control the ammonia level in your tank.

These bacteria create their colonies in the substrate of the aquarium or in the biological filter.

That’s why it is very important to get a high-quality filter for your aquarium. Because a good filter will have biological filtration that can help to keep ammonia levels under control in your aquarium.

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You should always make sure that your aquarium or fish tank contains optimum levels of oxygen.

There are a few signs that tell you that your aquarium doesn’t contain the optimum level of oxygen

  • If you notice your Oscar fish coming to the surface of the water of your tank very frequently gasping for air then it is a sign that your fish tank doesn’t contain sufficient oxygen.
  • If you noticed rapid gills moment of your Oscar fish then it suggests that your Oscar fish is struggling to get oxygen in your tank.
  • The fish also starts eating less food if there is a low oxygen level in the tank.

A simple and reliable way to increase oxygen in your fish tank is to introduce an air pump in your tank.

You can also plant some live plants to increase oxygen in your tank. Here is list of the best oxygenating plants.

Besides, here are some other ways to increase oxygen in your fish tank.


In the wild, Oscar fish live with other fish. So it is a good idea to keep some other species of fish with your Oscar. 

But Oscar fish is infamous for their aggressive behavior. And you may have heard stories that Oscar fish has eaten other species of fish in the tank.

They are all true! 

The thing is, Oscar fish is a predator fish and it will eat whatever fish that fit into its mouth.

On the other hand, Oscar fish can also get bullied or stress out if you keep other large and aggressive fish in your Oscar fish tank.

So, you have to be careful while choosing tankmates for Oscar fish.

I have written a detailed article about the best tank mates for Oscar fish here.

Can Oscar Fish Live Alone? (Yes, but…)


When it comes to the substrate for your Oscar fish tank you can use any substrate you like whether that is sand or gravel.

Oscar fish are very intelligent and they usually redesign their tank according to their liking.

And one of the things they do to redesign their tank is they move the substrate by taking it in and spitting it out.

So you should avoid substrate that has sharp edges or your Oscar fish tank.

Besides, the debris in your tank can get trapped into the substrate that’s why you should not have a very thick substrate. 1-1.5 inch substrate works well.

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You may have heard that Oscar fish don’t like plants. And if you keep live plants in their tank they will destroy it.

It can be true up to a certain extent.

As I said earlier, Oscar fish like to redesign their tank. So if for some reason they don’t like the plants in their tank, they will uproot it.

Besides, Oscar fish has a very unique personality and every Oscar is different than others.

Some Oscars will not bother if you keep plants in their tank. And others will destroy plants no matter what plant you keep in the tank.

But there are a lot of benefits of keeping live plants in the fish tank. They help to oxygenate the tank, they help to emulate their natural habitat, etc.

And there are some hardy plants that are usually compatible with Oscar fish.

I have written a detailed article about it here.

6 Tips to Take Care of Live Plants in Aquarium


Though Oscar fish are very aggressive they also like to hide behind objects and calm down.

Oscar fish usually hides behind plants for decoration in the tank. 

Decorations also offer you a chance to design your tank and give it a uniques look. And it also helps to emulate the natural habitat of Oscar fish. 

But, as I mentioned earlier, Oscar fish redesign their tank so they can move the decorations.

That’s why if you are planning to keep some decorations in your tank then you should make sure that they are large. So that your Oscar will not be able to move them.

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What do Oscar fish like to eat?

Oscar fish are omnivorous and there is a variety of food you can feed to your Oscar fish.

Flakes and pellets

Primarily you should feed high-quality Cichlids flakes and pellets to your Oscar fish.

Cichlids flakes and pellets contain all the nutrients that your Oscar fish need for its proper growth and development.

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Live or Frozen food

You can also treat your Oscar fish with live or frozen food like bloodworms, brine shrimp, etc.

You can also feed feeder fish like goldfish, guppies, etc to your Oscar.

I have written a detailed article on Oscar fish food and feeding here.

Tank maintenance

Nobody likes to live in a dirty, cluttered place.

To keep your tank clean, you should regularly keep up with the maintenance of your tank.

You should regularly check the water parameters of your tank. You can easily check them with a chemical test kit.

Besides, you should also regularly check the temperature of the water of your tank with a thermometer.

You should also regularly clean the glass of your tank to remove algae. You can easily remove the algae using an algae scraper.

Besides, as mentioned earlier, debris gets trapped in the substrate of the tank so you should regularly remove the debris from the substrate using a siphon.

What Do Oscar Fish Like In Their Tank infographic

How Long Do Oscar Fish Live?


Do Oscar fish like current?

In the wild, Oscar fish mostly found in the Amazon basin in the areas where there is a strong current.

So Oscar fish like current and your filter should be able to produce strong current in your tank. And you don’t need any air pump just to produce strong current.

Do Oscars prefer sand or gravel?

You can use either sand or gravel as a substrate for your Oscar fish tank.

One thing to note that Oscar fish take in and split out substrate in the tank. So Ideally you should use sand or fine gravel substrate in your Oscar fish tank.

13 Best Aquarium Plants For Gravel Substrate

How do I make my Oscar fish happy?

You can do several things to make your Oscar fish happy in your tank.

But it all comes down to providing the ideal environment to your Oscar by maintaining the ideal water conditions, keeping the tank clean and clear by doing regular maintenance of the tank and feeding high-quality food that contains all the essential nutrients that your Oscar fish required for their proper growth and development.

Do Oscar jump out of their tank?

Oscar fish can jump out of their tank. That’s why you should always put a lead on the tank of your Oscar fish.

Oscar fish usually jump out of the tank when they see something out of the tank they want to eat.

Or when they are not getting the ideal water conditions in the tank.

Can Oscar fish live without an air pump?

An air pump is not absolutely necessary for an Oscar fish tank. And your Oscar fish can live without an air pump if your tank already contains the optimum level of oxygen.

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Do Oscars play dead?

Oscar fish has a very unique personality and when they don’t like any change that you have made in their tank. Or if you have changed their food and they don’t like it then they have a tendency to sulk.

How many Oscars can you have in a tank?

You can have as many Oscar fish in your tank as you want but you just have to provide them large enough space.

The thing is, Oscar fish grow at a very fast rate and they can grow pretty large.

If you keep them in a small tank then they will produce a lot of poop in the tank. And then you will have to do water changes very frequently.

I have written a detailed article about tank size for Oscar fish here.

I have mentioned several products in this article that can help you to create and maintain the ideal environment for your Oscar fish in your tank.

If you need any of these products then be sure to check out my recommended products here.


So what do Oscar fish like in their tank? Basically, Oscar fish like the ideal environment in their tank.

And to provide them the ideal environment you have to maintain the ideal water conditions, provide them a large enough tank, and keep up with the regular maintenance.

If you do that your Oscar fish will live happily and thrive in your tank.

I hope you found this article helpful.

If you do, please share it!

Happy fishkeeping!

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Prathmesh Gawai
He is the main author and editor at Aquagoodness.com. And he loves to share helpful information on aquarium and/or fishkeeping hobby. Prathmesh has over five years of aquarium and/or fishkeeping experience. Currently, he has a Betta fish tank. He has written hundreds of articles on various aquarium fish species and on fish tank maintenance over the last five years. Connect with him on YouTube here. Learn more about him here.

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