How Big Can Oscar Fish Get? (How do you get your Oscar big fast?)

If you are wondering, how big can Oscar Fish get then you are in the right.

In this article, I’m going to answer the same question and I will also tell you what can you do to get your Oscar Fish big fast.

How Big Can Oscar Fish Get? (How do you get your Oscar big fast?) image

So, how big can Oscar fish get?

In captivity, Oscar Fish usually grows up to 11 to 12 inches and weighs below 3 lb. But if you take good care of Oscar fish then it can even grow up to 15 inches.

In the wild, Oscar Fish usually grows up to 14 to 15 inches and weighs up to 3 lb.

But there a few examples of Oscar Fish that are reported to grow up to 18 inches and weigh 3.5 lb.

Are Oscar Fish Good Pets?

What is the maximum size of Oscar Fish?

oscar fish

As mentioned earlier, in the wild, Oscar fish usually grow up to 14 to 15 inches and the maximum size an Oscar Fish can grow in the wild is 18 inches.

Whereas, in captivity, Oscar Fish usually grows up to 11 to 12 inches.

But the maximum size an Oscar Fish can grow in captivity is 15 inches, though it is not very common.

If you want to increase the chances of reaching your Oscar Fish to 15 inches in your fish tank then there are a few things you have to do from the very beginning.

Tank size

Tank size plays a very important role when it comes to the growth of Oscar Fish.

The thing is, Oscar Fish grows at a very fast rate.

Besides, they are very messy fish i.e. they produce a lot of waste.

In the wild, they get very large space to swim around and this is one of the reasons they grow very big in the wild.

You should try to emulate the same and keep it in a large tank then they are juvenile.

Besides, as Oscar Fish produces a lot of waste, if you keep it in a small tank then chances are the tank will get concentrated with ammonia which can affect the growth of your Oscar fish.

So, if you want to grow your Oscar Fish to its full size then you will have to keep it in a large tank from the very beginning i.e. when it is juvenile.

Oscar Fish Behavior And Intelligence

Food

Though Oscar Fish are omnivorous. In the wild, they mostly feed on meaty foods.

So, in your fish tank, you should emulate the same and feed them high-quality cichlid flakes and pellets which generally contain mostly meaty ingredients.

Besides, you should regularly treat your Oscar Fish with live or frozen foods such as bloodworms, brine shrimp, etc.

As Oscar Fish are omnivores, you should occasionally feed them plant matter such as fruits and vegetables like spinach, carrot, lettuce, boiled peas, etc.

Also, providing a balanced and varied diet is the key to the fast and full growth of your Oscar fish.

How Long Can Oscar Fish Go Without Eating?

Maintain ideal water conditions

You should also maintain the ideal water condition of your tank. Ans keep the water parameters under the ideal range that an Oscar Fish requires.

The ideal range of water parameters range for Oscar fish is as follows:

Temperature: 74 to 81° Fahrenheit

pH: 6 to 8 

Hardness: 5 to 20 dH

How long does it take Oscar Fish to grow full size?

Oscar Fish is one of the fastest-growing fish. It can grow at a very fast rate of 1 inch per month and this is one of the reason it is not recommended to the people who are just starting out with fish keeping

Usually, Oscar fish reaches its full size in around 1 year.

Are Oscar Fish Jumpers? (Can they jump out of the tank?)

How do you get Oscar Fish big fast?

There are several factors that contribute to the fast growth of Oscar Fish.

How do you get Oscar Fish big fast infographic

Tank size

If you keep Oscar Fish in a smaller tank then this can affect their growth rate.

Oscar Fish produces a lot of waste and when they are kept in a smaller tank there is a possibility that the tank will get very concentrated with ammonia.

The high ammonia levels can affect their growth rate. Worst, it can also cause diseases and even death of your Oscar Fish.

Nutrition

Nutrition is one of the most important factors for the faster growth of your Oscar Fish.

For their natural growth and development, you should try to emulate their natural diet.

Primarily, you should feed them high-quality cichlid flakes and pellets on a daily basis.

Cichlids flakes and pellets contain all the essential nutrients that your Oscar Fish requires for its proper growth and development.

Besides, you should regularly feed frozen or live food such as bloodworms, brine shrimp, etc to your Oscar fish.

Occasionally, you can also treat your Oscar with feeder fish.

But the problem with live food or feeder fish is that they carry a risk of transferring harmful bacteria and viruses in your tank that can lead to diseases.

So, you should get live food only from a reputed source.

As Oscar Fish are omnivorous, you should occasionally feed them plant matter such as fruits and vegetables like carrots, lettuce, apples, boiled peas, spinach, etc.

Before feeding these fruits and vegetables blanch them and cut them down into small pieces so that it will be easier for your Oscar to consume it.

Ideal water conditions

You should maintain the ideal water conditions that your Oscar Fish require in your tank.

You should try to emulate their natural habitat.

In its natural habitat, Oscar Fish mostly found in the Amazon basin where the temperature is slightly warmer.

Oscar Fish is intolerant to cold temperature and this is one of the reasons its distribution is very limited in the wild.

Oscar Fish are cold-blooded fish and they cannot regulate their body temperature. And thus, they depend on the water for maintaining their body temperature.

The ideal temperature for Oscar Fish is between 74 to 81° Fahrenheit.

You should try to keep the temperature within this ideal range.

Besides, you should also try to avoid frequent fluctuations in this temperature throughout the day.

If the temperature of the water of your tank is lower than the ideal temperature then this can damage the immune system of Oscar Fish.

An Oscar fish with low immunity is susceptible to diseases such as Ick and hole in the head.

The best way to maintain the warmer temperature in the tank is by installing a heater in the tank. Checkout our heater recommendation.

Besides, the temperature higher than 81° Fahrenheit is also bad for the health of Oscar Fish.

It can also lead to diseases.

In the case of high water temperature, you can use these ways to reduce the temperature in your aquarium.

The ideal pH tolerance range for Oscar Fish is between 6 to 8 and the hardness tolerance range between 5-20 dH.

Ammonia

Concentrated levels of ammonia can lead to diseases in your Oscar Fish.

Worst, it can be deadly to your Oscar Fish.

Ideally, your tank should not contain any ammonia.

To keep ammonia levels under control you should regularly check the ammonia levels of your tank.

If you noticed ammonia in your tank then to reduce the ammonia, first of all, you should immediately do a partial water change.

The newly introduced water will not have ammonia so it will dilute the concentration of the ammonia in the tank.

Usually, the permanent solution to a high ammonia level is installing a good powerful filter.

The filter not only keeps the water clean and clear, but it is also the place where beneficial bacteria make their colonies.

This beneficial bacteria helps to keep ammonia levels in control.

Besides, these are some other ways you can use to reduce the ammonia levels in your tank.

Oxygen

Oscar Fish require dissolved oxygen for their survival.

If your fish tank doesn’t contain sufficient oxygen levels then it can affect the growth rate of your Oscar Fish. Worst, it can also lead to diseases and death of your Oscar Fish.

So, you should always make sure that your tank contains optimum levels of oxygen.

There are a few signs that suggest that you are tank doesn’t contain sufficient oxygen levels

  • If you notice your Oscar Fish coming to the surface of the water of your tank gasping for air then it is a sign that your Oscar Fish is struggling to get oxygen in your tank.
  • If you noticed rapid gills moment of your Oscar Fish then it also suggests that your Oscar Fish is struggling to get oxygen in your tank.

In case of low oxygen, you should immediately do a partial water change to increase the oxygen level in your tank.

The permanent solution for low oxygen levels is to install an air pump in your tank. Check out our recommended Air Pump

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

Tank maintenance

For the optimum growth of your Oscar Fish, you will have to keep up with the daily, weekly, and monthly maintenance of your aquarium.

Daily maintenance

On a daily basis, you should observe the behavior of your fish.

If you notice any signs of disease or if you notice any unnatural behavior, for example, if your Oscar Fish coming to the surface of the water gasping for air very frequently. Then it is a sign of low oxygen in the tank.

By observing your fish on a daily basis, you can detect any health issues very early. And so you can treat it very easily.

Besides, you should also visually check the equipments like the filter, air pump, heater, etc of your tank.

After feeding your fish you should also remove any uneaten food from the tank. Because uneaten foods can spike up the ammonia levels in your tank.

As mentioned earlier, temperature plays a very important role in the proper growth of your Oscar Fish. So you should check the temperature of your tank on a daily basis.

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Weekly maintenance

On a weekly basis, you should siphon the substrate of your aquarium to remove debris from it. Check out our recommended Vaccum Cleaner or Siphon

You should also wipe down the outer glass of your aquarium with a cloth.

You should also remove the algae from the inner glass by scratching the glass.

Besides, you should also do a partial water change on a weekly basis.

Monthly maintenance

On a monthly basis, you should test all the water parameters of your tank such as pH, ammonia, nitrate, and nitrite, etc.

You should also change the filter media of your filter on a monthly basis.

If you have plants in your tank then you should also trim them if needed.

Can You Put Live Plants with Oscars? (Best Plants for Oscars)

Genetics

How fast and how big your Oscar Fish grow is also dependent on its genetics.

If you are doing everything fine but still your Oscar Fish is not getting as big as you wish it to be then it might be due to its genetics.

But at the end of the day, you have done whatever you can to give an ideal environment to your Oscar Fish to live happily and thrive which is a very good thing anyways!

FAQ

How many types of Oscar Fish are there?

There are about 13 different types of Oscar Fish.

Some of these Oscar Fish are natural. Whereas, the others are painted to get the color.

I have written a detailed article covering all the types of Oscar Fish with their images and videos here.

What size tank do I need for 2 Oscars?

A good rule of thumb to follow while keeping multiple Oscar Fish together is- 55 gallon for your first Oscar Fish and then add 20 to 30 gallons for every new Oscar Fish.

So, by following this rule, the ideal tank size for Oscar Fish is at least a 75-gallon tank.

I have written a detailed article about everything you need to know about the tank size of Oscar Fish here.

What kind of fish can live with Oscars?

Though Oscar Fish are infamous for their aggressive behavior there are some kinds of fish that you can keep with your Oscar Fish.

You can keep fish like Convict cichlids, Firemouth cichlid, Pleco, Silver Arowana, etc with your Oscar fish.

I have returned a detailed article covering the best tank mates for Oscar Fish here.

Basically, you have to keep in my a few things while choosing tankmates for Oscar Fish.

  • The fish should be large enough not to fit into the mouth of your Oscar Fish. Or else it is most likely going to get eaten by your Oscar.
  • The fish should be semi-aggressive so that it can hold its own if Oscar Fish try to harras it.
  • And the most important thing is the ideal water parameters that the fish require should be similar to that of Oscar Fish.

Can Oscar Fish Live Alone?

What can I feed my Oscar Fish?

There is a decent variety when it comes to food for Oscar Fish.

Primarily, on a daily basis, you should feed high-quality cichlids flakes and pallets to your Oscar fish.

Because it contains all the nutrients that your Oscar Fish requires for its growth.

Occasionally, you should also feed it frozen or live food like bloodworms, brine shrimp, feeder fish, etc.

As Oscar Fish is omnivorous, you should also feed fruits and vegetables such as carrots, spinach, lettuce, apples, boiled peas, etc to your Oscar.

I have written a complete guide about Oscar Fish food here.

Conclusion

So how big can Oscar Fish get?- In the wild, Oscar Fish generally gets about 15 inches long and weighs around 3 pounds.

In captivity, it usually gets up to 12 inches long and weighs below 3 pounds.

Oscar Fish can get bigger than 12 inches in your aquarium if you provide it the ideal environment.

I hope you found this article helpful.

If you do, please share it.

As always, happy fishkeeping!

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