How Long Do Oscar Fish Live? (In Captivity and in the Wild)

If you are wondering, how long do Oscar fish live then you are in the right place.

In this article, I am going to answer the same question.

In the wild, Oscar fish usually live up to 18 years. In captivity, Oscar fish usually live for 8 to 12 years.

The life expectancy of Oscar fish in captivity depends on the care it gets and the tank environment.

How long does Oscar fish live in captivity?

The life expectancy of Oscar fish in captivity depends on how you take care of it.

Usually in captivity, Oscar fish live for 8 to 12 years.

But if you provide it the ideal environment and high-quality food then it can live up to 15 years in your tank.

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How to increase the life expectancy of Oscar fish in your tank?

To increase the life expectancy of Oscar fish in your tank you have to provide it high-quality food and maintain the ideal environment in the tank.

Tank size

Tank size plays a very important part when it comes to life expectancy and the overall growth and development of your Oscar fish.

Oscar fish can get pretty big and produce a lot of waste. And this is the reason Oscar fish require a larger tank.

If you keep Oscar fish in a small tank then you will have to do the partial water change multiple times per week. If you don’t do so then the bioload will quickly build up in the tank. And it can affect the organs of your Oscar fish and reduce its life expectancy.

In fact, the bioload can be so harmful to your Oscar fish that it can even cause the death of the fish.

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

Ideally, you should keep Oscar fish in at least a 55-gallon tank.

If you keep it in a 55-gallon tank then the Oscar fish will have sufficient space to swim around.

Also, the bioload will not quickly build up in the tank. And doing partial water change once a week is sufficient to keep the bioload under control.

I have written a detailed guide on Oscar fish tank size here.

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Food

Optimum nutrition is essential to increase the life expectancy of your Oscar fish.

If you feed poor quality food to your Oscar fish then it can reduce its life expectancy.

Oscar fish are omnivorous but their diet mostly consists of meaty foods. So your Oscar fish’s diet should contain mostly meaty ingredients.

Flakes and pellets

On a daily basis, primarily you should feed high-quality cichlids flakes and pellets to your Oscar fish.

Because cichlids flakes and pellets contain all the essential nutrients that your Oscar fish require for its proper growth and development.

Live food

Live food is the most nutritious food you can feed to your Oscar fish.

In the wild, Oscar fish feeds on small live insects and fish.

So you should emulate the same in your tank. 

You can feed live food such as bloodworms, brine shrimp, mealworms, crickets, grasshoppers, etc to your Oscar fish.

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

The problem with live food is that it carries the risk of transferring harmful bacteria and viruses that can cause diseases to your Oscar fish in your tank.

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

Besides, you should not feed the live food on a daily basis and feed it as a treat.

Live food have a very short shelf life so you should feed it within 3 to 4 days of getting it.

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Frozen food

Frozen foods are also very nutritious for your Oscar fish

You can feed frozen food like bloodworms, brine shrimp, etc to your Oscar.

The best part about frozen foods is that it is very nutritious and it doesn’t carry any risk of transferring harmful bacteria, viruses in your tank.

Besides, frozen foods have a longer shelf life than live food. And they are also very convenient to store and feed to your Oscar fish.

Fruits and vegetables

As mentioned earlier, Oscar fish are omnivorous. So you should also periodically feed them fruits and vegetables

You can feed them fruits and vegetables such as apples, spinach, lettuce, cucumber, etc.

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Water conditions

Water condition plays a huge role in the proper growth and development of your Oscar fish.

In the ideal water conditions, your Oscar fish will thrive. And in poor water conditions, your Oscar fish will be vulnerable to deadly diseases.

Temperature

In the wild, Oscar fish is mostly found in the Amazon basin where the temperature is a bit warmer.

You should emulate the same and maintain the temperature between 74 to 81° Fahrenheit.

Oscar fish cannot survive in lower temperatures for a long time. In fact, this is the reason its distribution is limited in the wild.

To raise the temperature of the tank the easiest way is to install a heater in your tank. 

You just have to set the temperature on the heater and it will keep the temperature within the set temperature range.

You can check out my recommended heater here.

Besides, the temperature above the ideal range is also bad for Oscar fish. If you are struggling to keep the temperature low in your tank then these ways can help.

pH

The ideal pH for Oscar fish is between 6 to 8

Hardness

The hardness tolerance range of Oscar fish is between 5 to 20 dH.

Ammonia

High ammonia level is not only deadly to Oscar fish but any fish in the tank.

That’s why keeping ammonia levels in control is very important to keep your Oscar fish healthy and to increase its life expectancy.

Ideally, your tank should not contain any ammonia.

In the fish tank, what is called the beneficial bacteria, helps to keep the ammonia levels in control.

Beneficial bacteria make their colonies in the substrate of your tank and in the biological filter of your tank.

That’s why installing a high-quality filter is very important to maintain a healthy aquarium.

Besides, while cleaning the filter you should be cautious and follow the best practices. Or else, you will accidentally remove the beneficial bacteria from your filter.

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Oxygen

Oscar fish requires oxygen just as we do. But they require dissolved oxygen.

Your tanks should contain the optimum level of oxygen for the proper growth and development and to increase the life expectancy of your Oscar fish.

How to measure the oxygen levels in the tank?

There are a couple of ways to measure oxygen levels in a fish tank.

The first one is with a portable dissolved oxygen meter.

Using this meter you can easily measure the oxygen level in your tank. 

But unfortunately, a portable dissolved oxygen meter is quite expensive and honestly, you don’t really need it.

The other way is by using a chemical test kit that works the same way as other test kits that you use to measure hardness, pH, etc.

But usually, the chemical test kit used to measure the oxygen levels are very inaccurate.

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So what’s the solution?

Honestly, you don’t really need any dissolved oxygen meter or chemical test kit to measure oxygen in your tank.

You can tell if your of fishtank contains the optimum level of oxygen or not just by observing the behavior of your Oscar fish.

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Signs of low oxygen in a fish tank

  • If you notice your fish coming to the surface of the water very frequently gasping for air then it is a very clear sign that your tank doesn’t have the optimum level of oxygen.
  • If notice rapid gills movement of your fish then it suggests that your fish is struggling to get oxygen in your tank.
  • Eating less food could also be a sign of low oxygen in the tank.

So, if you noticed any of the above signs then chances are your fish tank doesn’t contain an optimum level of oxygen.

A reliable and permanent solution to increase oxygen in the fish tank is by introducing an air pump in the tank.

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

Tankmates

Ideally, you should only keep other Oscar fish in your Oscar fish tank as tankmates.

But you can keep other species of fish with your Oscar fish, you just have to be careful while choosing the species.

Oscar fish are aggressive and they are a predator fish. So if you keep other fish that are smaller than the size of the mouth of your Oscar fish then they are most likely going to get eaten by your Oscar.

So you should avoid keeping smaller fish like neon tetra with your Oscar fish.

On the other hand, if you keep very aggressive fish with your Oscar fish then it can bully your Oscar fish which can stress out your Oscar that can reduce the life expectancy of the Oscar fish.

So when it comes to keeping other species of fish in your Oscar fish tank, you should choose the species of fish that are large enough to not fit into the mouth of your Oscar fish and they should be semi-aggressive.

I have written a detailed article about the best tank mates you can keep with your Oscar fish here.

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Tank maintenance

As mentioned earlier, to increase the life expectancy of Oscar fish you have to maintain the ideal environment in your tank.

And to maintain the ideal environment in your tank you will have to keep up with the daily, weekly, and monthly maintenance of the tank.

Daily maintenance

On a daily basis, you should observe the behavior of your fish. This will help you to detect any health issue in your fish or any issue in your fish tank like low oxygen level, etc.

If you notice any unnatural behavior then you should note it down in the journal. And if you noticed the similar behavior for two to three days then you should look into the issue and figure out the cause.

Basically, you have to figure out if your fish is suffering from any disease. And check if the water parameters of your tank are within the ideal range that Oscar fish require.

You should also check all the equipments in your tank like the lighting, heater, filter, etc are properly working or not.

Also, ten to fifteen minutes after feeding your fish you should check if there is any uneaten food in your fish tank.

If you notice any uneaten food then you should remove it. Also, you should also cut down on the food.

Weekly maintenance

On a weekly basis, you should do a partial water change of your tank.

Besides, you should also siphon the substrate to remove any uneaten food or debris from your substrate.

You should also wipe down the outer surface of your tank on a weekly basis.

Monthly maintenance

On a monthly basis, you should perform water test to test the pH, ammonia, hardness level in your tank. You can easily test these things with a test kit.

You should also trim the live plants in your tank if necessary.

Also, you should change the filter media of your filter.

And you should also look check your lighting and see if it requires any light bulb replacement.

Overall to increase the lifespan of your Oscar fish you have to provide it the ideal environment. And to do that you have to keep up with the maintenance of your tank.

Fortunately, there are some tools that will make your job easier like a siphon, thermometer, algae scraper, etc.

You can check out my recommended tank maintenance tools here.

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How big do Oscar fish grow?

In captivity, usually, Oscar fish grow up to 11 to 12 inches long and weigh just below 3 lbs.

Whereas, in the wild, it can grow as long as 14 to 15 inches and weighs above 3 lbs.

If you take good care of your Oscar fish then it can grow larger than 12 inches, up to 15 inches in your tank.

Also, there are a few examples of Oscar fish that have grown up to 18 inches in the wild.

I have written a detailed article on this topic and I have also covered what you can do to grow your Oscar fish to its fullest potential here.

How fast do Oscar fish grow?

Oscar fish grow at a very fast rate of 1 inch per month.

When you get Oscar fish when they are small they look very cute and little fish. But they can grow very rapidly that’s why usually Oscar fish are not recommended for beginners.

FAQ

What are the different types of Oscar fish?

There are about 13 different types of Oscar fish

  1. Lemon Oscar fish
  2. Black Oscar fish
  3. Tiger Oscar fish
  4. Oscar fish
  5. Albino Oscar fish
  6. Golden Oscar fish
  7. Blueberry Oscar fish
  8. Black and white Oscar fish
  9. Green Oscar fish
  10. Lutino Oscar fish
  11. Fire Red Oscar fish
  12. Veil tail Oscar fish
  13. Florida Oscar fish

I have written a detailed article on this topic covering all the different types of Oscar fish with images and videos here.

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What is the ideal tank size for Oscar fish?

When it comes to tank size for Oscar fish a good rule of thumb to follow is 55 gallons for a single Oscar fish. And if you are going to keep multiple Oscar fish together then extra 20 to 30 gallons for every new addition of Oscar fish.

For example, for two Oscar fish, you will require at least a 75-gallon tank.

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What are the best tank mates for Oscar fish?

While choosing tank mates for Oscar fish, you have to keep in mind a few things.

  • The fish should be large enough to not fish into the fit into the mouth of your Oscar fish.
  • It should be semi-aggressive so that it can hold its own against Oscar fish.
  • Also, it should require similar water conditions that an Oscar fish require.

Some good examples of best tank mates for Oscar fish include Green terror, Silver Arowana, Silver dollar, Convict cichlid, Pleco, Blue acara, etc.

I have written a detailed article on this topic covering all the best tank mates for Oscar fish with their images and videos here.

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What do Oscar fish eat?

Oscar fish are omnivorous and they can eat a variety of food.

You you can feed them high-quality cichlids flakes and pellets.

You can also treat them with frozen or live food such as bloodworms, brine shrimp, feeder fish, etc.

As Oscars are omnivorous, you should also feed them fruits and vegetables such as spinach, lettuce, small pieces of apples and cucumber, etc.

I have written a detailed guide on this topic here.

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Conclusion

So how long do Oscar fish live?

In a fishtank Oscar fish usually live for about 8 to 12 years but it can live up to 15 years if you take good care of it.

In its natural habitat, Oscar fish live for about 18 years.

I hope you found this article helpful.

If you do, please share it.

Happy fishkeeping!

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