How Long Can Oscar Fish Go Without Eating?

If your Oscar Fish has suddenly stopped eating and now you are wondering how long can Oscar Fish go without eating or you are just curious to know then you are in the right place.

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

Oscar Fish can go anywhere between two weeks to up to four weeks without eating.

How much your Oscar Fish can go without eating depends on its age and size.

A juvenile Oscar Fish can go up to two weeks without eating and adult can go up to four weeks and even more without eating anything.

How Long Can Oscar Fish Go Without Eating? image

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Reasons your Oscar Fish is not eating and what to do about it

There could be several reasons your Oscar Fish is not eating in your tank depending on the situation.

Reasons your Oscar Fish is not eating and what to do about it infographic

New Oscar Fish

If you have a new Oscar Fish in your tank then there could be several reasons it is not eating anything in your tank.

  • Not acclimating

If you have not acclimated the Oscar fish before introducing it in your tank then it can shock your fish and that can result in your Oscar not eating anything.

The thing is, there could be a difference in the temperature of the water from where you bought your Oscar and the water in your tank.

If the difference is big then it can shock the fish.

So before introducing the fish into your tank, you should first acclimate it by keeping the polythene bag (in which you have you have brought the fish) floating on the surface of the water of your tank for at least 10 minutes.

And then you should net out the fish into the tank.

  • It takes 24 to 48 hours

After acclimating the fish and introducing it into the tank, it usually takes 24 to 48 hours for a new fish to start eating in the new tank.

  • Try live food

Even after 24 to 48 hours if your new Oscar Fish is not eating then you should try feeding it live food.

You can feed it feeder fish like Guppies, Shrimps, and Bloodworms.

Oscar Fish like live food so usually they start eating live food right away. And then you can start feeding other foods like Flake food and Frozen food, etc.

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Oscar Fish suddenly stopped eating

If you have Oscar Fish for a while in your tank and it was eating regularly and now it has suddenly stopped eating then there could be several reasons behind this.

Spoiled food

Nobody likes to eat spoiled food.

So if you are feeding spoiled food to your Oscar fish then this could be the reason it is refusing to eat the food.

  • Flake food

Flake food has a longer shelf life but the mistake people usually make is they get a large pack of flake food, open it and keep it feeding to their fish until it finishes for four to five months.

Though flake food has a longer shelf life once you open the packet its life decreased to about one month.

So after opening the packet of the flake food, you should finish it within one month or else it will get spoiled.

This is why you should get the packet of flake food that you can finish within one month.

  • Frozen food

The mistake people make with frozen food is that while feeding the Frozen food they take out the packet of frozen food and keep it outside of the refrigerator for a long time this reduces the life of frozen food.

So after opening the refrigerator, you should take out the amount of food that you want to feed to your fish and put the packet back into the refrigerator immediately.

  • Live food

Live food has the shortest shelf life so you should feed the live food within two days of getting it.

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Stray current

Stray current can also stress Oscar Fish and this could be the reason your Oscar Fish is not eating.

Now, this is a very uncommon reason but it can happen.

Usually, the water heater or powerhead is the source of stray current.

Stray current can also cause Hole in the head disease in your Oscar fish.

You can check if you are tank has stray current or not using a multimeter or grounding probe.

If you found your tank has stray current then you can replace the water heater and powerhead and it will solve the issue.

Not maintaining ideal water condition

If the water parameters of your tank are not within the ideal water parameters range that an Oscar Fish requires then it can stress out your Oscar. 

And this may be the reason your Oscar fish is not eating.

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  • Temperature

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

You should keep the temperature of the water in your tank within this range.

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

If you notice your tank has a low temperature then you can introduce a water heater to raise the temperature of the water of your tank.

Checkout our heater recommendation

  • pH

The ideal pH range for Oscar Fish is between 6 to 8.

So you should try to keep the pH level of your tank within this range.

If you notice the pH of the water in your tank is lower than the ideal range then you can add crushed coral to raise the pH.

If the pH of the water of your tank is high then to lower that pH you can add driftwood lower the pH.

Another way is to increase CO2 levels. You can do so by adding some live plants into the tank.

Now you may be thinking that increasing CO2 can harm the fish. Yes, it can but not when you increase it by adding live plants because live plants will also increase Oxygen in your tank.

Besides, there are a lot of benefits of keeping live plants in the aquarium.

  • Hardness

Oscar Fish can tolerate a wide range of water hardness.

Ideally, the hardness of your water should be between 12 to 15 DH.

If you noticed the hardness of the water is lower than the ideal range then you can add some crushed coral in your tank to raise the hardness.

To lower the hardness of the water you can add driftwood. It will soften the water.

  • Ammonia

Ideally, your tank should not contain any ammonia. If you noticed high ammonia levels in your tank then you can use these ways to lower the ammonia and get rid of it.

  • Oxygen

You should make sure that your tank contains optimum levels of oxygen. If you noticed any signs of low oxygen like fish coming on the surface gasping for air, rapid gills movement of gills then you can use these ways to increase oxygen in the tank.

Picky eaters

Oscar Fish are picky eaters and sometime they just don’t like to eat.

So you should not bother about it for up to 2 weeks.

But you should not just stop feeding your Oscar.

You should keep feeding it regularly and also remove uneaten food from the tank.

But after two weeks if your Oscar Fish is not eating then you should look for any signs of disease in your Oscar fish.

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How long can Oscar Fish survive in your tank without food?

How long can Oscar Fish survive in your tank without food really depends on its age and size.

If you have small juvenile Oscar Fish then it may survive up to two weeks or even less.

But if you have an adult Oscar Fish then it can survive up to one month or even more.

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How to feed your Oscar Fish when you are on vacation?

There are a few ways you can keep your Oscar Fish well-fed when you are away from your house.

how to feed your fish when you are on vacation infographic

1. Ask your neighbour or friend

This is the most reliable way to feed your Oscar Fish when you are on vacation.

You should also tell your neighbor or friend how much food they should be feeding your Oscar Fish every time. 

Because it is very easy to overfeed Oscar as they always seem hungry.

A simple way to tackle this problem is to get a pill organizer and then you should put the amount of food you feed your Oscar Fish in each small compartment of the pill organizer.

Then just tell your neighbor or friend to empty one box every time they feed your Oscar Fish.

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2. Use an automatic fish feeder

You can also use an automatic fish feeder to keep your Oscar Fish well-fed when you are on vacation.

You just have to load food into the automatic fish feeder and it will automatically dispense the food.

But the problem with the automatic fish feeder is that it may stop working or it may start dispensing a lot more food than necessary. And overfeeding the fish can also cause issues.

Thats why you should only use a tried and tested automatic fish feeder.

Check out our recommended Automatic Fish Feeder

3. Use slow release fish food

This is a very cheap way to keep your Oscar Fish well-fed when you are away from the house.

The slow-release food is basically blocks of food that you can toss into your tank and it will automatically break down over few days.

There are two different types of slow-releasing fish food.

  1. Weekend feed fida blocks
  2. Vacation feeder blocks

If you are going away for the weekends then you should use the weekend feeder blocks.

If you are going on a longer vacation (up to two weeks) then you can use vacation feeder blocks.

Below is a table that shows different types of slow releasing fish food and their validity.

BRAND LASTS FOR SUITABLE FOR
TetraPond14 DaysPond fish
Tetra Weekend14 DaysTropical fish
Zoo Med14 DaysBottom feeder
Zoo Med Mini7 DaysGourami and small fry
Zoo Med Betta7 DaysBetta
Pyramid Automatic feeder3 DaysAll types of fish

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How often should I feed my Oscar Fish?

If you have a juvenile Oscar fish then they require more food than adults for their faster growth.

So you should feed them 3 times for a day.

If you have adult Oscar Fish then you can feed it a couple of times for the day.

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Conclusion

So Oscar Fish can live anywhere between two weeks to more than four weeks without eating anything.

But how much your Oscar Fish can survive really depends on its size and age.

Juvenile Oscar Fish may not last more than two weeks but a large Oscar Fish can survive more than four weeks.

I hope you found this article helpful.

If you do, is share it.

As always, happy fish keeping!

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Author
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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