My Oscar Fish is Breathing Very Heavily – Should I be Worried?

By Nadine Oraby | 2020 Update

If you discover that your Oscar fish is gasping for air, in other words, it appears as if it is breathing heavily it could be a sign that there is something malfunctioning for various reasons.

It is quite important to make a thorough check-up as it could perhaps be hazardous and cause fish pain and danger.

My Oscar Fish Is Gasping For Air | Difficulty Breathing (Video)

Water and Illness

One common thing about all Oscar fish is the importance of providing it with healthy aquarium water. Therefore you need to put a considerable amount of effort in having regular check-ups and assuring that its quality is at top and maintaining it that way.

Whereas the Oscar fish does not require the same attention in terms of food. It is of paramount importance that it lives in an environment with a high standard.

It is an advantage if you have more than one fish. This way you can find the problem easily; if more than one fish shows indications of the same problem, then it is more likely that the problem is linked to the water conditions.

But first things first, start by checking the oxygen and mineral levels. It is normal for any fish to open and close their mouth regularly, that is simply the way they breathe, but if it is too quickly, it means they are making a huge effort trying to inhale oxygen.

Water Maintenance

Back to the water and its condition; here are some guidelines on how to check that the quality of the water in the fish tank is good.

It is important you test the water rather frequently. Pay attention to whether the water is warm or not. The warmer the water is, the less oxygen it will contain. The best way is, evidently, installing a thermometer in the aquarium.

Also, examine the quality of the filtration as it can be damaged, see if it is transporting back the water correctly. The most advantageous solution is changing pads oftenly.

As mentioned before, if water is the problem then all you Oscar fish will suffer. Are they all breathing heavily? Other contents in the water to look for are ammonia, the pH level, nitrates and the like. As for the pH-level, a neutral value is the best, which is 7.0 more specifically.

Space in the Tank

The condition of the tank could be another cause; the water is affected by the tank’s poor condition, consequently lowering the water quality.

Naturally, if it is an old tank it would be in a worse condition than a new one.

Upon purchasing new fish, another critical aspect worth acknowledging is to pay attention to certain details at the pet store such as how it is being stored. Is the tank clean? The fish per se, is it healthy? You do not want to bring home ill fish and by so doing ensuring that it will infect the healthy fellow fish!

If some fish fall ill, it is sound to separate the contaminated ones from the healthy. If you have another tank, that would save you plenty of time. Another positive aspect, you can simply put the fish in the other tank and find out if it reacts the same way or differently.

Given that the Oscar fish is a fish that needs a perfect environment; it also has to have plenty of space. A crowded tank is not ideal for this fish. It has to have far more liberty than that, give it a spacious field where it can move and play freely!

Finally, be careful not to medicate the whole tank. That is wasting a great deal of healthy water in vain.


It is, since most pet owners are not experts on treating ill pets, tricky diagnosing the fish if they have trouble breathing.

Here are some basic guidelines that are simple to follow single-handedly at home.

First of all, if there is an ill fish, try as soon as possible to separate the healthy fish from the ill ones. Here it comes in handy having more than one tank at home. Even if you do not have that many fish, in case of this you can place them in a healthy environment.

An infectious parasite could potentially infect all fish. You can tell an infection from a couple of signs; following an infection caused by parasites the Oscar fish will change its color at the gill area. Another sign is that it will turn slimy too, which is, in general, a common sign of infections.

Related Questions

Why should I examine my tank water? The water should be examined thoroughly because there could be poisoning due to nitrates, ammonia, or nitrites.


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