How to Care for Oscar Fish?

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The reason why the Oscar Fish is popular among fish keepers is its colorful patched body. This species comes straight from the South American rivers.

Although they might seem innocent while calmly swimming around in the tank, they actually have a rather aggressive temperament.

Therefore, you need to be careful about which fish breeds you want to put them together with. Oscar Fish are indeed very attractive but they need special care, therefore we would recommend them for experienced aquarists.

If you take care of them, feed them properly and choose the right tank mates, you will be able to admire their appearance and character for a long time.

It is interesting to watch how Oscars behave and interact with other fish and their environment in general. Fish enthusiasts consider them rather intelligent and playful community fish.

Follow our guide and we will show you how to set up an aquarium and take care of an Oscar Fish with little effort.

Oscar Fish Tank Conditions

Oscar Fish Tank Conditions

Oscar Fish Tank Conditions

The best way to ensure the well-being of most fish species is to keep them in a tank that resembles their natural habitat. The Oscar Fish is no exception and, in their case, you need to set up a warm freshwater type of aquarium.

Oscars are river fish that don’t mind strong water flow in the tank. The water flow generated by most filters is enough for them. Although they mostly live in the Amazon and similar rivers where the sunlight is strong, it doesn’t quite shine through the fuzzy water. Therefore, it is better to install dim lights.

With soft sand at the bottom of the tank, plants that rise to the top and a few rocks here and there, the Oscar Fish will have a great time in your aquarium. Just make sure to add some bigger rocks or any other decoration where they can hide if they want to.

This species enjoys digging into the substrate so it shouldn’t contain anything hard or sharp. When the Oscar starts looking for food, it does so vigorously. Therefore, it is recommended to fix the decoration to prevent them from being moved.

Decorating the tank with plants is a great idea, although Oscars tend to pull them out once they get busy looking for food. One great solution is to buy only plastic plants. Since they love to dig in the gravel, they will eventually rip out the living ones anyway.

When it comes to the equipment, this species doesn’t need anything out of the ordinary. All you need to buy is a filter and a heater to keep the water warm enough for them. Any type of lighting is fine as long as it is not too strong. Oscar Fish got used to slightly dim light in the nature.

It is important to mention that whatever equipment you have, it has to be fixed to the tank because the Oscars can move those too. Also, make sure to install a lid on top of the aquarium to prevent them from jumping out.

The ideal water temperature for Oscars is 74-81°F with a pH of 6-8 with 5-20 KH alkalinity to prevent pH drops. Aquarists looking to keep this breed should opt for a big fish tank with at least 55 gallons of size. Having an aggressive temperament, Oscar Fish can get tense and irritated if their territory gets invaded by other species.

Giving your Oscars enough space also reduces the likelihood of them getting diseases. You can start with a 55-gallon aquarium and then every additional Oscar will require 20-30 gallons more in order to live undisturbedly and healthily.

Oscar Fish Diet

Oscar Fish Diet

Oscar Fish Diet

This is the easiest part. Supplying the food that the Oscar Fish prefers to eat is really not that big of a deal. And the thing is that they will eat pretty much everything you give them.

Since they are omnivores, they eat both plant and meat-based foods. They don’t prioritize anything as long as it falls under one of these two categories.

It is best to go for the simplest option and just buy some flakes in the store. There are many aquarium fish foods that are designed specifically for omnivores, providing them all the nutrition they need.

Juveniles grow surprisingly fast if you feed them properly. However, flakes are not the type of food they might want to hunt down.

You can give them some prey such as Rosy Red Minnows or Goldfish from time to time. Keep in mind that these fish won’t really provide your Oscars the nutrition they need.

They contain a huge percentage of fat, which is bad for them in bigger quantities. The feeder fish we mentioned are just for spicing up their diet. It has to be balanced at all times.

If you want to see the Oscar Fish in action, then give it some brine shrimp, bloodworms or daphnia. These are the type of foods that are not only full of protein but also activate their hunting instincts. Preparing something for them to eat at home is really not a big deal.

Cut a couple of green vegetables into tiny pieces and your Oscar will be more than happy to eat it. The reason why they need veggies is because they get a lot of Vitamin C from them. In order to guarantee the well-being of this fish breed, it is recommended to stick to a diverse diet. This way, they will surely get all the nutritients they need for a healthy life.

Breeding Oscars in Aquarium

Breeding Oscars in Aquarium

Breeding Oscars in Aquarium

When it comes to breeding, there are specific conditions that have to be met for the Oscar Fish. This is pretty much a feat you need to gather a lot of information about.

The thing is that they are rather picky so adding just any fish from the opposite sex doesn’t work. It is best to give the Oscar Fish many options and let it go through its natural choosing process.

To make things easier for the fish keepers, shops often sell established Oscar pairs that are ready to breed. It is a great start to buy a pair of Oscar Fish right away and thus leave the hardest part behind.

This instantly gets you through the first step. However, if you don’t want to skip it, then the best way to do it is to buy a few juveniles and put them together.

As they spend their time together, they will get used to each other and it will be more likely for them to form mating pairs. This is only recommended for patient aquarists as it takes 1-2 years until the Oscar Fish reaches maturity. It is also not easy to distinguish between males and females.

It is called “monomorphic” when there are no specific characteristics that indicate the sex of a fish breed. The males and females look pretty much the same. It will be a complete mystery unless you take a close look at their genitals. What you need to look for is a single sharp spike which signifies that the Oscar you are looking at is actually a male.

Females have their own egg tube which is only visible during breeding season. In their natural habitat, Oscars breed during rainy season. They simply won’t be aware of if unless there is no raining going on.

You can simulate this easily with a sparkling water surface and by lowering the water temperature a degree or two. It can be noticed by the fin waggling of the female that she is ready to spawn.

Then, the female and its mate will find a clean rock surface where you can expect a couple thousand eggs to be laid. The parents will be busy guarding them for 2-3 days and then once the eggs are hatched, they take care of their juveniles.

It is best to remove the small Oscars as soon as possible and put them into another, sponge filtered aquarium. There, you can keep an eye on them and feed them 2-4 times a day until they get bigger, then move them back to the main tank. We can conclude that Oscar Fish is one of the hardest species to breed but it is surely not impossible.

Oscar Fish Tank Mates

Oscar Fish Tank Mates

Oscar Fish Tank Mates

Eating tank mates and being aggressive toward them are two of the main traits of the Oscar Fish. When you take a look at them in their natural habitat, it might seem like they can get along with plenty of other fish around them. However, a fish tank is much smaller and it triggers different behavioral patterns.

The Oscar Fish being a territorial species will be rather frustrated being around other breeds and sharing the same space. Your best shot is to not mix them with other species. If you are committed to the idea of creating a community aquarium, then you need to choose tank mates carefully.

The rule of thumb is to stick to bigger fish with peaceful attitude. Oscars are cichlids themselves and their tank mates should be from the same family. You can consider adding some Green Terrors, Jaguars, Jack Dempseys, Firemouths, Bichirs or Severum Cichlids to your tank, just to mention a few.

There are literally no smaller fish breeds that can be in the tank without the Oscar being a potential life threat to them. Make sure that your community aquarium is large enough so that each fish can establish its own territory without any conflict.

Oscar Fish Common Diseases & Treatments

Oscar Fish Common Diseases & Treatments

Oscar Fish Common Diseases & Treatments

It might happen that one day you will notice a few holes in your Oscar’s head. This is commonly known among aquarists and it’s simply called the Hole in the Head disease. In the beginning, a couple tiny white holes or patches will appear on the head of the cichlid.

Once you see this, you can be sure that your fish got the disease. The patches will first turn into holes, then those can slowly turn into fissures. This means that certain protozoa and bacteria have infested the organism of the Oscar Fish.

Fortunately, this can be treated by giving them antibiotics such as Flagyl. The fact that this disease appeared in your tank means that there are certain conditions that are not met for this species. It is better to avoid this disease by keeping the water clean and properly filtered.

On the other hand, a crowded community aquarium not only makes the Oscar Fish aggressive but also makes it more prone to diseases. It is best to keep them in a large enough tank where every one of them can live comfortably.

If you want to give your Oscars some live feeder fish, be aware that you can add foreign bacteria to your tank along with them. Even the fish you feed them can potentially make them sick.

Do Oscar Fish Bite You?

It might be tempting to put your finger into the water in hope that your favorite Oscar will bump into it, appreciating its owner. This is not exactly what is going to happen. They will rather try to bite it, which can hurt but it definitely won’t do much damage.

Oscars are not powerful biters. They are suction feeders with small harmless teeth. You will only feel their jaws, as their teeth are inside where they can’t reach you. Even if they try their hardest to bite you, the worst-case scenario will be an almost unnoticeable abrasion.

It is important to note that you don’t even have to put your finger into the water in order to interact with your Oscar Fish. Since they recognize their owner, all you need to do is walk into the room and they will notice, wiggling their fins and head excitingly.

If they feel comfortable in your presence, you can even take off the lid and feed them with your hand.

Will Oscar Fish Jump Out of Tank?

If your Oscar Fish spots something outside the tank that looks like food, it won’t be afraid to jump out in hope of getting it. In their natural habitat, they get very excited if they find an insect. They want to quickly get there and eat it.

Unfortunately, even water droplets that roll down in front of them can look like food for Oscar Fish. Therefore, they have to be kept in closed aquariums. Make sure that the lid on top is fixed properly because Oscars can simply lift lighter ones and jump out anyway.

How Long do Oscar Fish Live?

These beautiful fish can live for 8 to 12 years on average. If you pay close attention to the tank conditions and their diet day by day, then you can prolong their lifetime up to 15 years. Giving them both plant and meat-based food for proper nutrition is key.

The second important thing is to buy a big enough aquarium according to how many Oscars you want to care for. Smaller fish tanks only cause them to be stressful, which can shorten their life span. Not to mention that keeping them in a small space can halt their growth.

Are Oscars Good for Beginners?

Oscars are surely not the easiest fish to keep, especially not in a community aquarium. For beginners that want them anyway, it is highly recommended to not mix them with any other species. It can save you a lot of headaches.

Things are certainly easier for fish keepers who know how to choose tank mates for fish with aggressive temperament. The Oscar Fish is yet another kind of territorial fish that doesn’t tolerate other breeds. It is recommended to read about their needs and behavioral patterns before you get one.

For example, one of the most difficult things about the Oscar Fish is the breeding process. If you want juvenile Oscars, then you really have to plan things out in advance.


If you want to add an Oscar Fish to your community tank, then you better plan it out in advance. It is certainly better to add them first than to mix them with other fish in an already established aquarium community. In fact, the easiest way to go about it is to set up an Oscar only tank.

More experienced aquarists can choose from plenty of other cichlids that can form a nice community with the Oscar. Although this requires a big tank and specific conditions, it is definitely wort the effort. You can populate your aquarium with extraordinary fish that flourish in many different colors. All you need to do is follow this guide to avoid any complications.

Not to mention how delightful it is to watch as the Oscars swim around and interact with their environment and other fish around them. If you follow our guide, you will be able to set up a fish tank for this breed without any complications. The challenge of getting the Oscar Fish to breed will only make it more fun to keep them.

avatar I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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