Oscar Fish Care: Tank Mates, Food, Size & More

Oscar fish (also known as velvet cichlids) are an extremely popular freshwater fish in the aquarium community. They’re beautiful and their mannerisms make them quite fun to watch.

However, there are some things you need to know about Oscar fish care if you plan on owning one.

You see, these fish are quite aggressive and can quickly cause problems if you intend on keeping them with other fish. That’s why we always recommend that you have some experience as an aquarist before owning one.

But don’t let us discourage you! Oscars can be incredibly rewarding aquarium fish to care for, and once you know what you’re doing it’s rather straightforward.

That’s why we wanted to put together this care guide. In it, you’ll learn everything you need to know about Oscar fish care and helpful facts about the species.

Species Summary

Oscar fish come from South America, namely Peru, Brazil, French Guiana, Colombia, and Ecuador. Their scientific name is Astronotus ocellatus (if you’re curious about that sort of thing). Large numbers of these fish can be found in the Amazon River basin, and prefer slow-moving water with lots of rocks and debris.

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Although they are naturally from this area, you can also find them in Australia, China, and even Florida. Oscars that are found here have either escaped during fish trade transit or dumped by owners who could not take care of them.

They are known for their stunning looks, unique personality, and aggression.

Oscar Fish Lifespan

The average Oscar fish lifespan is somewhere between 10 and 13 years. However, an Oscar with great genetics and good care can live to be over 15 years old!

Their lifespan is often overlooked by potential owners, and once they learn this they are often blown away. When you compare this to other related fish like the African cichlid there’s a big difference in age.

In our opinion, this is one of the biggest benefits of getting an Oscar fish. We love the idea of owning and caring for them over a long period of time.

In our experience, the bond and attachment you build when having a fish for that long really makes the experience that much more rewarding!


The appearance of Oscar fish can vary between the types, but all of them look fantastic. The beauty of this tropical fish is something that can’t be said enough!

Oscar fish care recommendations

The general body type of these fish is rather long and egg-shaped. Just like many other cichlids, their caudal fins are pretty symmetrical and standard, not sticking out too far.

Their dorsal fins run all the way down to their caudal fins, giving them a sort of beefy look. The same thing goes for their anal fins as well. This makes them look kind of like chunky torpedoes in the water.

Their eyes are large and are typically surrounded by an uncolored patch on their bodies that extends up to the start of their dorsal fin.

Types Of Oscar Fish

Below we list the different kinds of Oscar fish and what they look like.

Tiger Oscar Fish

This is the classic color pattern that you see with most Oscars. As you can probably tell by the name, tiger Oscar fish are black and orange.

Unlike tigers, they don’t have orange stripes (or is that black stripes?) and instead have a more sporadic pattern. They have a black body with orange lines and blotches that extend in random directions.

It kind of looks like a mix between a Rorschach test and a maze. Their body is usually free of color from their upper lip to the start of their dorsal fin.

Red Oscar Fish

Red Oscar fish are pretty much exactly that, red. The red coloring is mostly on their sides and unlike the tiger variation, is hardly patterned. They are mostly solid red on the side with no color on any of their fins.

Albino Oscar Fish

Like many other species in the aquarist community, albino Oscar fish are highly sought after due to their unique look. With albino Oscars, the red coloring on the side is typically more scattered than the orange on the Tigers. It’s also more of a “large shape made of dots” kind of design as well.

Albino Oscar fish near the substrate

As you probably guessed, the main body color of albino Oscar fish is white. We’ve had the opportunity to see a few of these over the years and they definitely steal the show when you’re observing a tank!

Black Oscar Fish

Black Oscar fish are another neat type that is on the rise lately. They have a very similar side pattern to the Albino but instead, the colors are 100% stealth.

Black and grey are the dominant colors and it gives them a unique look especially when compared to the louder alternatives that other types offer.

Lemon Oscar Fish

The Lemon Oscar fish is basically the same thing as the red Oscar, just yellow. The color patterns on their sides follow the same kind of rhythm, it’s just done with different colors.


The average Oscar fish size is somewhere between 10 and 12 inches long when in captivity. When in their natural habitat this fish can exceed the 14-15 inch mark.

Due to their large size, you need to make sure Oscars have the proper space to thrive and live a comfortable, low-stress life. We cover tank size in the following section.

Oscar Fish Care

If you want to provide good Oscar fish care, there are a handful of things you’ll need to do. While a large part of keeping this fish happy revolves around managing their temperament, you need to get the basics right first.

Although these fish are hardy, you never want to rely on that. Providing them with the best possible living environment should always be the goal.

Tank Size

The ideal Oscar fish tank size should be at least 55 gallons. These are large fish, so they need a large tank that can accommodate them.

If you’re planning on owning multiple Oscar fish, then you’ll need to ramp up the tank size. Plan to add at least 25 additional gallons of water for each new Oscar you add.

This means for one fish you’ll want (at minimum) a 55 gallon tank, 80 gallons for two, 105 gallons for three, and so on.

Ensuring you have the proper tank size should always be step one for trying to provide great care for your Oscar fish. After all, this is the home that they’ll be living in!

If they don’t have enough room to be comfortable their health will suffer due to stress. Not only that, but the aggressive nature of this fish can be amplified when confined to a small space (not fun for anyone involved).

Water Parameters

Next, you want to make sure that your water parameters are within the recommended guidelines. This will make a massive impact on the lifespan of your Oscar fish and will ensure their health over time.

  • Water temperature: 75-80°F
  • pH levels: Between 6 and 8
  • Water hardness: 12-15dH

You won’t need to worry about fancy filtration or lighting, which makes Oscar fish care a little easier. A standard filter and light will do just fine. You don’t even need to worry about air or water pumps to produce the necessary amount of current.

Lastly, make sure you’re consistent about doing water level tests. Significant water changes can lead to serious health issues for your Oscars.

What To Put In Their Tank

Having a good tank setup is extremely important as well. Plenty of inexperienced aquarists think that all you need to worry about is water quality parameters, and putting a lot of effort into what goes inside the tank is a waste of time.

We can’t express just how wrong this is.

The way you set up your Oscars tank will significantly impact their enrichment and stress levels over time. If you want them to be happy and healthy, pay close attention to this section!

  • Hiding places: It’s important to give your Oscar fish a place to hide so they can feel comfortable and safe. Rocks and driftwood are great options. Oscars aren’t picky though, so anything that will serve as a suitable hiding spot is fine with them.
  • Plants: If you want to add plants to their tank it’s usually smart to go with a plant that can float like Hornwort. They won’t be damaged by any of the digging Oscars do and will grow like a weed no matter what you throw at them.
  • Substrate: You’ll want to make sure there’s a soft substrate on the bottom of the tank. Oscars like to root around and churn through the substrate on occasion, and you don’t want them to get cut while doing this.

Hole In The Head Disease

There’s one disease that you’ll want to keep an eye out for with Oscar fish in particular. It’s called Hole in the Head disease and it is definitely not something you want your fish to get.

The symptoms are one or two small holes in the head of your Oscar. These will get worse over time if left untreated, and will likely cause scarring after they have recovered.

As gruesome as this sounds, Hole in the Head disease is something you can cure and also prevent. Maintaining great water quality within the recommended parameters will pretty much guarantee that your fish won’t get this disease.

If you see that your fish is developing this disease then it’s time for you to get to work. You’ll need to do water tests and likely change the water in the tank of you find that there are issues. This guide is a great resource that goes into each step of the process.

Food & Diet

When it comes to the best Oscar fish food, you have a number of options to choose from. This is because Oscars are not picky when it comes to what they eat (they’re omnivores)

In their natural habitats, Oscars typically eat insects, the occasional fish, and will nibble on whatever plants that strike their fancy.

In your freshwater aquarium, you’ll likely be feeding them a mix of processed and live food. Pretty much any cichlid-friendly pellets or flakes are just fine. For live food, two of the most common solutions are brine shrimp and bloodworms. You can even feed them live crickets and grasshoppers.

If you want to experiment with some additional foods to supplement the diet of your Oscar fish, there are a few other options. Some aquarists have experimented with occasionally feeding their Oscars nuts or fruits, but this is something you’ll want to limit quite heavily.

Frozen peas have also been reported to provide a nice boost in energy and the richness of color in your fish (they also seem to love them). Again, this is Oscar fish food that you’ll want to reserve as a special treat.

Behavior & Temperament

Oscar fish behavior is something that can be misunderstood. When people hear that this fish is aggressive, they sometimes think that they are downright mean.

That’s not the case.

Yes, Oscars have the potential to be quite aggressive and territorial. However, this will typically only show if you have them in a suboptimal tank environment.

Tiger Oscar fish exploring the tank

Being too crowded or pairing them with tank mates that aren’t a good fit is a recipe for disaster. But if you’ve done your homework and have them in an environment where they feel comfortable, your Oscars can actually be pretty mellow!

Aside from their aggression, there’s one Oscar fish behavior that’s worth noting before we move on (we hinted at it above). These fish love to scrounge through your substrate in an attempt to dig up some food.

This means you need to be prepared for them to occupy the middle (where they spend most of their time) and bottom of the tank throughout the day.

Oscar Fish Tank Mates

With their potential for aggression, finding the best tank mates for Oscar fish is obviously a priority for many new owners.

If you want to play it safe the best tank mates for Oscar fish, are other Oscar fish. This is a pretty common rule when it comes to aggressive species of fish.

All you need to do in this case if make sure you follow the minimum tank size protocols and you should be good to go!

Community Tank Mates

If you want to keep your Oscars with tank mates of another species you’ll have to be a little more careful.

Due to their aggression, the confined nature of a freshwater aquarium makes it difficult to fully guarantee there won’t be conflict (even if your tank size is large enough). 

This means you’re going to have to look for fish that are large enough to hold their own but won’t feel the need to pick a fight.

Small fish like goldfish or guppies will be toast if kept in a tank with Oscars. If you’re using them as feeder fish that’s a whole other story of course.

Some good Oscar fish tank mates include:

  • Bichirs
  • Blue Acara
  • Jack Dempsey Fish
  • Green Terrors
  • Silver Dollar Fish
  • Arowanas
  • Chocolate Cichlids
  • Demon Earth Eaters (awesome name btw)
  • Firemouth Cichlids
  • Black Convict Cichlids
  • Plecos
  • Banded Leporinus

As you can see, there are a lot of cichlids on this list of potential tank mates. This is because their feisty nature can usually cancel each other out and result in peaceful cohabitation.

Author Note: It’s important to monitor your fish closely when you introduce them to each other. Like people, some are grumpier than others. You might find that you have two tank mates that are just too feisty to live together (even if they’re from a species on the list).

Breeding Tips

If you’re planning on breeding Oscar fish, we wish you luck. These fish are extremely difficult to breed and require a great deal of experience in order for you to pull it off.

With that being said, it is possible to breed Oscars.

One of the challenges you’ll face right off the bat when it comes to breeding Oscar fish is how picky they are when it comes to mate selection. This is usually what causes most breeding attempts to grind to a halt.

A workaround for this is purchasing two fish that have already mated, or grown up together. The disadvantages of this are cost and time, but it’s your best bet if your current Oscars won’t mate.

To mimic the time of year that Oscars mate there are a couple of things you’ll want to do. The first is to lower the water temperature just a little bit (a few degrees is fine). Doing some partial water changes every 2-3 days is also another way to encourage the mating process.

If this works you’ll see some different behavior from your fish when they’re ready to mate. There will be some fin shaking that looks a bit unusual at first. They might also open their gills a bit more than normal. If you see this that’s a good sign, nothing to worry about!

In the breeding tank, you’ll want to make sure there are rocks available for them to lay their eggs (before this process starts of course). That’s because your Oscars will use the top of a rock as a place to lay their eggs.

Once this has happened the pair will pretty much hover around their eggs until it’s time for hatching. You might see the female moving some of the substrate out of the way to keep the eggs clean (this is very fun to watch).

After two or three days the eggs will hatch and you’ll need to find a new home for the juveniles that helps them facilitate their growth. Feed them a few times every day and monitor their growth. When they start to get too big you’ll need to make sure that they get an upgrade in tank size so they can continue to grow normally.

It’s Decision Time

Now that you know more about Oscar fish care and their general temperament, it’s up to you to decide if you want to take them on.

In our opinion, the difficulty of Oscar fish care is blown a little out of proportion by some people in the aquarist community. There are definitely some things you’ll need to take seriously, but as long as you follow the recommended steps everything should be just fine.

We think the upside of owning Oscars is well-worth any of the considerations you need to make about their aggressiveness. They are a fantastic and beautiful fish that can be loads of fun to observe.

If you have any suggestions on how we can improve this guide we would love to hear from you. Just visit our contact page and get in touch!

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