Oscar Fish has Swollen Stomach – Should I be Worried?

A reoccurring issue that strikes many Oscar fish is the stomach problems they suffer from. Here we will discuss how to approach the matter.

Should you be worried if your Oscar has a swollen stomach? Yes! Oscar fish are sensitive to abdominal stress and are not that resilient. Treating them quickly is a pressing matter and you might, unfortunately, find scarce supply of medical resources at home.

Oscar Swollen Stomach (Video)

Treating the fish is critical because such a situation can lead to a lot of complexities.


This is going to be a rather serious article as the question will present some disturbing answers. But it is of great relevance to be straightforward, for the sake of the good.

The sooner you cure your fish, the better.

You would then ease their pain and suffrage as well. The Oscar fish is highly receptive and sensitive to stomach problems. Quite frankly it might end up dying even when treated at an early stage.

Do not take this as a given though. This is how it is in general. We will unfold the whole picture here and hopefully if you find your Oscar fish suffering from a stomach issue, you will find a way to help it through its agony. Fingers crossed!

There can be many kinds of stomach problems. The swollen stomach per se is not the cause, it is a symptom. This leaves us with more unanswered questions as we have to dig deeper.

Usually the stomach appears swollen at a later stage, after years sometimes, and the cause is generic. It could be a tumour perhaps. At this stage, the process of curing is complex.

A tumour needs a surgery in order to be removed. This is a delicate process and it might be fatal too, as the Oscar fish might not survive the medical procedure. If the fish has developed a viral infection, you cannot fully treat the fish on your own with homemade medication. In these particular situations, a professional is a must!


The swollen stomach is one symptom. Along with it you can also discover other symptoms. The eyes can, as a result of an infection, swell up too. This phenomena is referred to as the eyes being pop-eyed. Antibiotics can cure the ailment. It is a possibility definitely worth going for.

Constipation is another illness. It may sound harmless; nevertheless it sadly is not. To the Oscar fish it is a critical condition. Not as serious as dropsy though. You will notice it from the way the fish starts swimming; uncontrollably and irregularly. The abdominal region does not have any movement, instead it looks swollen and enlarged.

A medical fast is recommended, if you notice a lack of improvement the fish might be suffering from dropsy. Then you will distinguish other warning signs too. More specifically: a soft or firm swelling in the abdomen, bigger eyes, and a constant loss of appetite.


The optimal solution is to seek professional advice and help as stomach issues are a very serious health concern. If you do not have the right expertise nor experience, it might result in a worse and more fatal situation.

If you decide to heal the fish on your own here are some steps to follow. Concerning the bloated stomach, make sure the fish is not pregnant so to speak. When you start the cure, you should have a quarantine tank where you place the ill fish. Do not keep the healthy ones accompanied with the sick fish.

Eating and fasting measures will be extremely beneficial at this stage. Eating habits of Oscar fish is special. It is not as picky about its foods as with the habitat it lives in. This does not exclude the fact that it cannot eat all sorts of food recklessly without any consequences. For a couple of days, try initially to give the fish very small portions of fresh food, or whenever possible, have it fast. If the health condition improves, then the pain was caused due to inappropriate food.

If we pay attention to the aquarium itself, there could be something malfunctioning there as well. A quick solution if you have a pet store nearby is bringing a water sample to them and have it analysed, treating the water may be a way out of the problem.

Bad water conditions can indeed cause disease which is why the vital importance of keeping a fresh tank is always stressed the vital importance of keeping a fresh tank.

How to avoid the stomach illnesses?

In general, two basic steps you ought to aim at excelling in:

  • Keeping the condition of the aquarium and the water clean, and keeping just enough fish (less here is far better than more!)
  • Giving the fish a healthy diet. It is by fact known that Oscar fish can eat from a varied and heterogenous food menu, but in order to prevent harmful stomach conditions be extra cautious with what you feed it with. Give it an extra care.

Do not forget that the viewable stomach symptoms can appear a long time after the actual problem has occurred!

Test the tank water frequently and make sure levels of ammonia and nitrates are within acceptable limits. The water in the tank should under no circumstances be less than perfect.

The temperature should be between 74-81 degrees Fahrenheit. To ensure it is the correct temperature, install a thermometer in your tank.

Furthermore, the mineral levels should be within reasonable limits as follows:

  • Ammonia: 0 ppm
  • Nitrites: 0 ppm
  • Nitrates: under 40 ppm

Besides the thermometer, other materials should be changed, like pads and filters, and on a regular basis. If you are to purchase more fish, make sure it is in good physical shape, and for a stronger guarantee that it is healthy, keep it in a separate tank for a couple of weeks at first so you have no doubts it is ill in any way or carries harmful parasites.

Learning more

Even if you are not a vet, read more about your fish and what needs they have.

As with all living creatures, the sooner you treat the fish, the greater chance it has to recover. Better be safe than sorry; do not wait long with visiting the local pet shop or clinic.

They can give you advice on what is going on with the fish and inspect more thoroughly and accurately. Hopefully, it won’t be fatal!

Related Questions

Could the fish be pregnant? Yes. It is tricky finding out if the fish is male or female though. Also check if it may be overdue because it might need some medical attention to help it lay the eggs.

Should I treat the fish on my own?If you want to treat your fish on your own, commence with natural methods and gradually increase to harsher methods. But better being safe than sorry; visit a pet clinic. They can give you advice on what is going on and inspect more thoroughly and accurately.


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