Oscar Fish Care – Tank Requirements, Feeding, and Breeding

It is no secret that Oscar fish have left the wilds and now proudly adorn our aquariums. These colorful fish have become sweethearts in places that they have found home all over the world.

For them, home isn’t just about the wild rivers that they are native to. Home is anyone who opens their arms and home to them.

There are however a couple of things that a prospective Oscar fish owner needs to put in place in order to give their Oscar the best care possible.

The things the Oscar owner would need to keep a healthy Oscar are diverse and they will all be discussed below. 


Before you bring your Oscar home with you, you have to know that you cannot keep it in a tub or bucket or anything of that nature. Oscars are prone to jumping and even making other fish jumps. Besides… they need a proper aquarium because that is when they are best kept. The care of Oscar fish starts with your choice of tank. Oscars aren’t tiny fish. 

At full capacity, Oscars can be quite big and thus they need space. A lot of it. He need to be able to do a 369° turn at any point in the aquarium. No matter what you do, we recommend that your Oscar fish tank should not be less than 152 litres of water strong.

Big fish, big filters

As earlier stated, Oscar fish grow to be rather big. This means that they will require a big tank. Another implication of the big tank and the big fish thing is big filters. 

See… the bigger the animal, the messier the cage. This also applied to Oscars as they are more prone to dirtying their water faster than most smaller fish species. The fact that they are big also means that they make a lot of poop. This is why you need a good and strong water filter to filter out and maintain their winter regularly.

If you refuse to use a filter, or the filter you use is not big enough or strong enough to handle the aquarium, you may have a constantly dirty aquarium in your hands. This means that you  need to do water changes more often.

If however you neither get a good enough filter or change the water frequently, your Oscar fish may start to develop diseases. In the long run, you would have spent quite a lot more in veterinary trips than you would have spent on a strong filter. 

A good and  strong water filter helps you maintain optimum water health and by extension … optimum fish health.

Ideal Aquarium Temperature

In case you do not know or are not sure, Oscars are not like every other fish. They don’t like to be in cold water. In their natural habitat far away in the Amazonian rivers, there is a certain water temperature that is consistent with those waters. It’s this temperature that makes the place ideal for Oscars.

The basic temperature that is best for Oscar fish at any level or location is between 23 to 27 degrees Celcius or 77 degrees Fahrenheit. Oscar fish love warm waters.  An aquarium heater that has a temperature controller will ensure the stability in temperature inside the tank. 

Regular Water Changes

Water quality is as important as water temperature. Oftentimes, when we talk about water change, People thinks that they are supposed to empty their fish tank and pour a completely brand new water k to it. However, the truth is that you really just have to change about 10-15% of the water in the tank.

The amount of water that needs to be changed would typically just freshen the water and not empty it out completely. Also, it only needs to be done once a week and can be automated .

Water quality often helps with ensuring good health for the fish. The harmful bacteria in the water is drastically reduced especially when taking into cognizance the use of filters to keep the water as fresh as possible in the course of the week.

Regularly tests for toxicity in water

Water test kits can be bought in many aquatic pet stores. Invest in a good quality water test kit. You could look out for a strong one that checks for multiple parameters once a week. This helps your aquarium to stay healthy for your fish. 

Aquarium water can sometimes be toxic without even looking like it is.  You cannot detect the exact toxicity of water just by looking at the water. That is why you need your own water testing kit.

Chemicals like ammonia can be detected through this device. It is also good to monitor water pH.

Oscar fish Nutrition

Having talked about the living conditions of the fish, yet another thing that the Oscar fish owner has to know is how to feed them. You see, an Oscar fish in the wild often knows how to balance its nutrition and keep itself healthy. They have to depend on humans when they are in captivity.

There have been studies done in what oscar fish can eat, prefer to eat, and should eat. The following paragraphs will focus on these three segments and talk about them in depth.

What Oscar fish can eat?

To be honest, Oscars can eat virtually anything that will fit in their mouths. It is weird but considering how Intelligent these fish are, one would expect them to be more conscious and picky. 

But no… these colorful Gill creatures eat virtually anything. From plants to animals to other fish and they might even attempt to eat your finger if you bring it near enough. 

This information is very important so that you would know to not let things fall into their tank. They will attempt to swallow anything that appeals to them so try to keep things that aren’t edible away from them. From plastic to silicon to metals or anything else really.

What Oscars like to eat?

When Oscars are in the wild, they depend mainly on food they can find in the deep rivers and river banks. Some of these food often inçlude a lot of insects like crickets, locusts, grasshoppers, mealworms and even garden worms.

They all contain a good abundance of vitamins.  Oscars are also known to have a taste for Prawns and shrimps. 

They find that these are absolutely fantastic meals because of the high fiber content which helps Oscar’s digestive system. You can also Cut up pieces of fish such like tuna or salmon for your Oscar to eat.  Squid is yet another meal that Oscars absolutely love because of its texture.

What Oscars should eat?

Now it is important to know that what Oscars can eat and what they should eat aren’t necessarily the same thing. Oscars can eat almost anything from bananas to bread but that is not to say that you should feed your Oscar either. 

Your Oscar doesn’t just depend on the water to keep them healthy. Oscars are actually heavily dependent of their nutrition for health and nourishment. If you feed your fish food that is not rich enough in the necessary vitamins, you may be setting them up for ill health. 

An unhealthy diet will not only contribute to illnesses and disease, but it may actually be the catalyst for such diseases as HITH disease. Also known as the hole in the head disease.

A lot of fish owners think that hole in the head is caused by poor water conditions but the reality is that bad nutrition is also a huge factor in the development of this ailment.

Oscar fish will eat virtually anything. The responsibility of making sure that they eat what is good for them rests on you. 

What you should feed your fish

Feed your Oscar fish with food such as prepared fish food such as crayfish, insects, and worms. They should also eat a lot of fresh fruits and vegetables because of their high need and dependence on Vitamin C. 

Yet another food item to feed your colorful swimmers are Algae & Plants. You could also feed them some high quality cichlid pellets. They have been created especially for the fish and already co rain a wide variety of vitamins and proteins. 

If you choose to feed your fish with pellets, always go for the best quality as anything less might not be so good. 

How often and how much should I feed my Oscar 

Most adult  Oscar fish will thrive with being fed just once per day. However, you have to be consistent with the feeding timing in order to prevent the fish from starving. On the issue of how much food the Oscar should eat, you need to feed your Oscar as much as he will eat. But not overfeed it. 

Feed your Oscar fish slowly and wait for it to clear out the last back before you give it more. It can keep the water clean and free of excess ammonia.

Can Oscar fish eat too much?

Yes… you can feed your Oscar too much. At the beginning of each feeding, your Oscar will rush its food. But as the feeding progresses, he is likely to alow down. When your fish slows down and is only picking one after the other, that is your cue to stop. At this point, your fish is no longer hungry and just being opportunistic.

Avoid overfeeding your Oscars. Also avoid dry foods as these may cause constipation. 

Should I feed Live Foods?

Experts say feeding live foods increases growth rate. But if you feed your fish live good that is contaminated with parasites, you may end up giving them food that causes diseases like endoparasites. 

Do not feed your fish mammalian flesh. They may cause your fish to develop fatty liver disease. You may also want to avoid feeding your Oscar with small fish like goldfish. These may carry diseases. 

What to do to heal constipation in Oscar fish?

Green peas have been known to help Oscars digest their food.  They are rich in vitamins and fiber. You can also feed your fish fruits like orange and watermelon but you have to ensure that all the seeds have been removed before you feed it to the fish. This will help eliminate the risk of blockage.

Yet another very important thing to do is to remove all uneaten. Food from the tank. If you don’t remove the food from the tank, it will decompose and spoil the water faster. It may even promote the growth of ammonia in the water.

Oscar fish care during breeding

Oscars are not mammals. Your oscar fish will lay eggs in water after fertilization. They often lay their eggs in clutches of 100s about two to four days after mating with the male. They usually lay about 1000 eggs over a period of five to ten days. 

Oscars rarely hatch all their eggs in the wilds. This is because there are too many odds against them. From the fact that the mother Oscar herself may eat some of the eggs to other fish eating them too. Even water currents may sweep them away and by the time the fry have matured very few of them actually make it into adulthood.

The average Oscar fry hatches within 72 hours. They have a higher chance of survival in the tank than in the wild. But even so, the slightest feeling of great may cause great damage to the young ones. The Oscar mom may eat her own fry if she feels threatened. 

It may become imperative that you separate the adults from the young ones after they are hatched. This may help them avoid being eaten by their own parents out of fear or distress.

How to know Oscar fish gender

Oscars look exactly the same irrespective of their gender. It is almost impossible to tell the difference in sex unless you can take a look at the shape of genital papillae. The genital papillae are located around their anal opening and it is blunt and wide-mouthed in females.

The most definite way to know you have a male or a female could be when they start to mate. You will observe them doing the mating dance and that’s when you will know that you have a male and female.

If you want to be sure then, it’s best to buy fish that have already established mating and reproduction a few times. It will help you know that you have a male or female or both.

How to know Oscar fish are mating

Reproduction is a normal part of existence. If you have a male and female Oscar fish together, you are very likely to experience these two matings. The mating ritual will seem to you like a fight at first because they will chase each other all over the place. Those finned friends of yours may also nibble at each other. 

They may also start to move sand and stones around in the tank. Your fish may favour corners when they are depositing this sand. This behaviour is often followed by the two mating and laying eggs. 

Oscar fish are delicate during this period and you need to handle them with care. The best you can do is to feed them and leave them alone. The best way to take care of them is to let them be. 

Feed them just enough during this period to avoid over contamination of the water. 

Perhaps most importantly though, you need to take the adults out of the water as soon as possible. Separate them from the fry and put them in another tank. This is to prevent them from eating the fry in the long run.

Oscar Fish Diseases, Prevention & Cure

There are five diseases that affect Oscar fish.

They  are;

  • hole in the head,
  • ich,
  • popeye disease,
  • fin and tail rot, 
  • and bloat.

The biggest causes of these diseases are overcrowding and bad water quality. 

Most Oscar fish diseases are influenced by vitamin C deficiency,  water changes or over-chemical filtration with activated oxygen chemical medium.

You can prevent them by monitoring them periodically and diligently for injuries or diseases at regular intervals of time.