Why Is My Oscar Fish Laying On Its Side?

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If your Oscar fish is lying on its side and you are wondering what’s happening to the little creature, there are a few possibilities to be considered. Sometimes, it is a normal behavior. In certain cases, it can be a serious issue (especially if your fish is breathing hard and not eating) that can lead to fatality if left unaddressed or untreated.

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Why Is My Oscar Fish Laying On Its Side?

If your Oscar fish is leaning quite heavily on its side, it can be due to stress, higher ammonia or nitrite levels, pH imbalance, temperature swings, swim bladder disorder, bacterial/fungal infection, or your fish is dying.

But remember, at times, laying sideways and acting dead is nothing more than a weird antic of Oscars.

Oscar Fish Laying Sideways – Normal or Alarming?

As long as your Oscar is eating and can swim normally, you can let go of the worries.

An Oscar may sulk to the bottom and lay on its side for a while when experiencing stress. Any kind of change in the environment can be a stressor for this fish, such as being introduced to a new home, water changes, or even the movement or addition of decor items.

If your Oscar isn’t eating, try offering some food it absolutely can’t resist – anything apart from the staple diet. Maybe feed some bloodworms. If your fish remain uninterested in the food, it’s likely due to sickness or disease. Labored breathing and discoloration are majorly noticed in such conditions.

There is no point in guessing or speculating how grave the situation is until you have thoroughly examined the fish for any signs of bacterial or fungus infection and have water test results available.

What To Do When Oscar Is Laying On Its Side & Not Eating?

By just looking at the fish, you can’t tell what’s causing it to lay sideways. To come to the point of figuring out the probable cause, you have to perform the following tasks.

Check Temperature & Water Parameters

Reportedly, Oscar fish laying on its side is highly related to water quality issues. Mainly, it’s due to excessive nitrogen-based toxins.

The first thing you do is, using an aquarium test kit, check the water for ammonia, nitrate, nitrite, and pH.

Ammonia and nitrite should always measure zero. Nitrate should be maintained below 40 ppm. And pH is best when kept between 6-8.

If your test readings confirm a higher amount of toxins, it means you are doing fewer water changes or your tank is small for the amount of bioload it produces. Oscars are famously messy and produce a lot of waste. Therefore, strong filtration is a must to maintain a clean, healthy aquarium.

Besides optimal water conditions, a steady temperature is another crucial factor for Oscar fish. Being tropical freshwater Cichlid, they prefer a temperature range of 74–80°F (23–27°C) all year round.

Make Water Changes

Does your test result measure excessive ammonia or nitrite levels? If yes, you need to change partial water until the ammonia/nitrite gets 0.

If your water column has excessively high amounts of toxic nitrogen compounds, as an immediate step, do a 50% water change. After that, you can perform a 25% water change every other day until you have achieved the ideal water parameters.

While removing the water, also remove the uneaten food particles and gunk off the substrate bed.

The replacement water should be dechlorinated and roughly of the same temperature as the aquarium water.

Feed Blanched Peas

A swim bladder issue or constipation can cause an Oscar fish to sink at the bottom of the tank and lie on its side.

If your fish look bloated or have a distended belly, take it as a tell-tale sign of swim bladder problems. It can be caused by overeating, gulping air, low water temperatures, bacterial infections, parasites, or other impaired organs affecting the bladder.

However, in Oscars, overeating is most often a cause for swim bladder issues as they have a habit of stuffing themselves with food which can result in indigestion or constipation. Also, Oscar fish are exceptionally creative at doing the food-begging dance, which makes it easy to fall into a habit of overfeeding.

Feeding shell-removed blanched peas works is undoubtedly the best remedy for a boated/constipated fish. Always go for frozen peas over canned peas, as the latter may contain salt content.

Most importantly, if your Oscar is suffering from constipation, you must withhold the food until the fish is up and swimming around normally.

Is Your Tank Overstocked?

Lack of space is another major factor for stress in Oscars, or any other fish for that matter. Also, it is cruel. Overstocking (if it applies to you) can be a possible reason why your fish is lying on its side.

A minimum of 55 gallons is required for a single Oscar. Ideally, a 75-gallon tank is better because Oscar fish grow fast and big. The larger the aquarium, the easier it is to maintain.

Moreover, they are messy fish, so you are going to need a good filtration system and have to carry out periodic water changes.

How To Know If My Oscar Fish Is Dying?

If your aquarium isn’t overstocked, the fish have no signs of fungus or stomach bloat whatsoever, the water is at optimal condition, and you have done everything in your power, but still, your Oscar remains lying on its side with fins clamped, breathing heavily, and not eating, it indicates that your fish might be dying.

Also, when an Oscar fish is on the verge of death, its eyes may pop out or get clouded up.

One thing to remember, illness isn’t always a cause of death. Sometimes it can be age as well. The average lifespan of an Oscar fish is about 10-13 years. So, if your fish is anywhere closer to that, the cause is self-explanatory.

How To Know If Oscar Fish Is Dying?

Final Words

Watching your Oscar fish lying on its side, not eating, is indeed a worrisome situation. If the cause isn’t visible, such as no signs of fungus, parasites, or stomach bloat, you should first test water parameters and make changes as required.

If that doesn’t improve the condition of your Oscar, feed blanched peas to rule out any possibility of constipation. Make sure there are no stress-inducing conditions or activities taking place in the aquarium.

When nothing seems to be going your way, as a last resort, you may have to perform euthanasia to end the pain of your beloved pet.