Can Flowerhorn and Oscar Fish Live Together?

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Both Oscars and Flowerhorns are popular choices for cichlid enthusiasts. These exotic species come in a variety of colorful morphs, so they’re guaranteed to transform your aquarium into the center of attention.

But can you keep these two together? If so, what should you look out for? Find out the answers in this article! We’ll be going over the similarities and differences between the species, as well as some pros and cons of each.

By the end of this article, you’ll know exactly how to keep these two in the same tank. So, let’s get started!

Are Oscar Fish Compatible with Flowerhorns?

If you’re searching for suitable tank mates, look no further! Oscar fish and Flowerhorn are one of the most compatible duos you can find. Being part of the same family (Cichlidae), they have more in common than you’d expect.

Why is that? Well, for starters, they come from the same geographical area, a.k.a. Latin America. Well, kind of.

Oscar fish naturally inhabit the waters of tropical South America. Given their natural habitat, they’re adapted to warm temperatures and have a pretty low cold tolerance.

Their natural habitat also makes them a hardy species capable of withstanding slightly alkaline water with high general hardness.

The origins of Flowerhorns are a bit more complex because this species doesn’t actually exist in the wild. It’s been created in captivity through selective cross-breeding. Created in the early 90s in Asia, the Flowerhorn is a hybrid between multiple cichlid species.

The parent species include the Central American Red Devil Cichlid and Trimac Cichlid, as well as the Taiwanese Blood Parrot Cichlid.

Given its genetic makeup and its parent species, the Flowerhorn naturally prefers very similar water parameters to the Oscar Cichlid.

Flowerhorns are equally hardy and prefer warm water. Besides their preferred environments, both species have similar temperaments. It should be easy to accommodate both of them in the same aquarium.

How to Keep Oscar with Flowerhorn?

So, we know that Oscars and Flowerhorns are compatible. Great! But not so fast! That doesn’t mean you can just pop a new tankmate into your Oscar tank, or vice-versa. There are a few things you should keep in mind before building the perfect mixed tank.

These include:

Behavioral Differences

Cichlids in general are notorious for their hotheaded personalities. This family of fishes contains some boisterous specimens, and Oscars and Flowerheads are no exception. Flowerheads in particular are very aggressive and easily agitated.

Oscars can be classified as semi-aggressive fish. They’re less likely to feel provoked by other tankmates. But both fish species are highly territorial, especially the males. You’ll need to set up the tank just right to avoid aggression between the fish.

I suggest pairing only fish of a similar size. Milder and smaller Oscars won’t stand a chance against a much larger Flowerhead fish. Also, ensure there’s enough space in the aquarium.

To keep territorial disputes at bay, provide at least 55-75 gallons worth of tank space for each fish. Adding plenty of plants, hiding spots, and maybe even some acrylic tank dividers will also help.

Size Differences

As I’ve already stated in the previous point, you should only pair Oscars and Flowerheads that are similar in size. You can also house Oscars with smaller Flowerheads. These precautions matter because Flowerhead Cichlids are stocky and powerful.

They can easily injure other fish, especially fish that are smaller than them. And Flowerhorns will reach 12-16 inches in length when fully grown. Males are larger than females and have more prominent head bumps. You can also choose shorter-bodied varieties of Flowerhorns.

Bonsai and Balloon Flowerhorns, for example, only grow up to 6 inches in length. Oscars only reach around 11 inches at most, and that’s when fully grown. Juveniles can be as small as 2-3 inches long. You might have to wait until your Oscars reach their full size before creating a community tank.

Dietary Needs

Luckily, this is one of the parts where the two species are very much alike. You won’t have to prepare anything special, as both fish eat exactly the same things. They’re both omnivorous, but with a big appetite for meaty foods.

Insects, larvae, bloodworms, small crustaceans like brine shrimp and krill, and high-quality cichlid flakes and pellets should form the staple of their diets. Live, dried, or frozen foods are all suitable. Just remember to thaw frozen foods or soak dried foods before feeding.

To prevent digestive issues, you’ll also have to include some plant matter in their diets. Things like algae pellets, blanched spinach, boiled peas, zucchini, and cucumber all contain gut-healthy fibers that aid in fish’s digestion and excretion.

Plants also contain unique vitamins, minerals, and pigments that the fish can’t get from just meaty foods.

Feeding Schedule

The two species eat similar omnivorous diets. But their feeding schedules will be a little different. I should also mention that both species are middle and top feeders, so they might often intersect and compete for food.

This is all the more reason to separate your fish with an aquarium divider. This will make your job a lot easier.

Just know that Flowerhorns are ravenous and greedy feeders. Overeating is a common issue that can cause all sorts of digestive problems. You need to portion out their food with smaller, more frequent meals. Ideally, Flowerhorns should eat 2-3 small meals a day.

A good portion would be anything the fish can eat in less than one minute. This species also benefits from one fasting day a week. Not feeding your Flowerhorns for 24 hours once a week allows their digestive systems some rest. This helps keep issues such as bloating and constipation at bay.

Oscars don’t suffer from the same issues as Flowerhorns. They require less frequent feeding, around once or twice a day at most. Only juvenile Oscars need to eat 2-3 times a day. They can also enjoy larger portions. You should feed Oscars a quantity they can consume in 2-3 minutes.

Water Parameters

And finally, we’ve reached a very important part of your tank setup. Setting and maintaining the optimal water parameters is crucial to keeping healthy, happy fish. Luckily, as we’ve discussed, Oscars and Flowerhorns have very similar needs in this regard.

Hardy Oscars need warm water, the ideal temperature being between 75-80°F. The water should be only slightly acidic to alkaline, with a pH of 6.0-8.0. Oscars also require hard water with a general hardness around 12-15dH.

Flowerhorn Cichlids have almost identical requirements. Their ideal parameters include warm water (80-85°F) that’s slightly acidic or alkaline (6.0-8.0 pH). They are more adaptable to various levels of water hardness. Compared to Oscars, this species can live in soft to very hard water (6-20dH). Obviously, it’s very easy to find a happy medium between these two species.

Oscar Fish vs Flowerhorn – Which to Choose?

Oscars and Flowerhorns can make a decent combo. But maybe you don’t want to risk putting two aggressive species in the same tank. Maybe you only have enough tank space for one fish. Which one should you choose?

To help you decide, I say we take a look at some of the pros and the cons of each species.

Let’s see how these two measures in terms of:

Price and Accessibility

There’s no other category where the balance tips more in favor of Oscars. They’re quite cheap and easy to find. You can buy juveniles for just $8-9 at any Petco or Petsmart shop. Flowerhorns are a different story.

These are designer fish, so they’re going to be expensive and difficult to find. A healthy, high-quality specimen can cost upwards of $300! You’ll also have to buy the fish online. You might find cheaper Flowerhorns, maybe a little under $100. But these specimens are often older and not as healthy or vibrant.


This one is a matter of personal preference. Do you want a stocky, powerful-looking fish? Then the Flowerhorn is the best choice. This fish has a wide, square-looking body. It has pointy elongated fins and of course, the signature hump on its head.

This species can come in a variety of colors, including blue, pink, red, yellow, purple, and albino.

Oscars have more elongated, streamlined bodies and shorter fins. They also have no hump. I think they look elegant and well-proportionated.

They also come in interesting colors such as golden, black, blue, green, copper, and albino. And let’s not forget some of the most popular and striking morphs like the tiger and veil tail Oscars.

–  Behavior

Both species are aggressive. However, Oscars are a milder flavor of feisty. Their personalities can vary quite a lot. You might get some very docile Oscars or some very touchy ones. Flowerhorns are mostly aggressive all the time.

They’re like Chihuahuas of the fish world, except they can actually do real damage. Mad at other fish, mad at you, mad at the world, the Flowerhorn Cichlid will never stop stewing in its own anger.

It’s harder to find a company for them. They need tankmates strong enough to put up with their aggressive behavior.

Lifespan and Common Diseases

Oscars are pretty straightforward. You give them a pristine tank, stable water parameters, and good food, and they’ll live for 10-20 years! That’s potentially more than the average housecat. Pretty impressive!

I should mention that Oscars are predisposed to HITH (hole in the head disease). This only happens when the fish has a poor diet and lives in unsanitary conditions. Take care of these two factors, and Oscars are not any more likely to experience poor health than other fish.

Flowerhorns are wildly unpredictable. They can live anywhere between 2 years to over one decade. They’re highly hybridized and you never know where they’re coming from. With no way to track back their breeders, you may discover some unpleasant surprises.

It’s not uncommon for these fish to suffer from genetic abnormalities that greatly reduce their lifespan. And you’ll have to pay a lot of money for a healthy, high-quality specimen. Also, no matter how healthy they appear, most Flowerhorn fish are infertile. This is a direct result of crossbreeding.


Finding a suitable tankmate for Flowerhorns is a challenge. You’ll need a similar-sized fish that can stand its ground. Oscar fish fit this description.

They’re equally territorial, semi-aggressive, and grow up to 11 inches in length. Keeping these two species together is therefore manageable.

They also have similar diets and water parameters. However, you need to be cautious during feeding. Flowerhorns are greedy eaters and they need small, frequent meals. Oscars can take in larger portions and they eat less often.

Overall, you can make this combination work nicely. Especially if you add an aquarium divider during feeding.

Just ensure there’s enough room for both fish species. Providing 55-75 gallons worth of aquarium space for each fish will reduce aggression to a minimum.

Author Image Fabian
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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