Discus Fish & Oscar Fish – Can You Keep Them Together?

If you’re looking for the most complete guide on whether you can keep these two fish species together, then you have come to the right place. Can you keep discus fish and Oscar fish together?

No, you should not keep discus fish and Oscar fish together, because discus fish are very shy and gentle while Oscar fish are very aggressive species that will attack almost any fish, even bigger ones.

However, discus fish are much more peaceful and won’t look to step into any fights. They can be vulnerable to potential aggressors, and are also somewhat delicate.

So that’s the main reason that you should not consider these two fish species in the same tank.

There are also other subtle differences between the two fish that would prevent you from keeping the two together successfully and peacefully.

There are differences in their diets, their size, but also in water requirements. Discus fish will require slightly higher temperatures than most fish, including Oscar fish.

It’s a shame that we can’t keep these two fish together. They are both very beautiful and unique in their own way. Let’s take at a few factors of why you shouldn’t keep these two together.

Behavior Difference

The main factor, the elephant in the room here is obviously their differences in behavior. Oscar fish are known as a very aggressive fish that will attack any fish that comes in their way.

They will turn very territorial, especially if they feel like another fish is too close to them.

But nevertheless, they are also very likely to attack other fish for no particular reason.

They like to show their dominance in the water tank. Also, these fish are very likely to hunt down smaller fish and make a meal of them.

On the other hand, discus fish are far more delicate and they are also a peaceful fish species. That’s why you should avoid pairing these two together.

While discus fish can, occasionally, get aggressive towards other fish, you are likely to see the peaceful version of them.

Most likely, they will get aggressive towards other cichlids, and they won’t put any other fish species at risk.

They are also shy fish, which is really the opposite of Oscar fish, which can be very flamboyant and aggressive.

That’s one of the biggest reasons why you should avoid keeping these fish together.

Size Difference

The size difference is not a big one, but Oscar fish might grow larger than discus fish. The Oscars will grow to about 12 inches in size, while discus fish will grow to about 8-10 inches in tanks.

While this might not seem like a great deal of difference, it will make a difference when they are placed together in the tank.

The discus fish is slightly smaller, which is why it would be almost unable to protect itself against potential attacks from Oscar fish.

And pair that with their shy and delicate behavior, and you will see that these two fish will not get along very well. Discus fish would be too intimidated to come out of hiding places, and they could even get hurt by the Oscar fish.

Water Requirements

Another big reason as to why you should avoid pairing these two up are tank conditions. Mainly, they are very different in terms of water requirements.

While Oscar fish will prefer temperatures of between 72-81 degrees Fahrenheit, it’s a well-known fact that discus fish will require much higher temperatures than most fish species.

They will need anywhere between 82-88 degrees Fahrenheit, which is quite a lot, especially for home aquariums.

Oscar fish would struggle to live in such a hot water, and their highest temperature limits would not be high enough for the temperatures of discus fish.

There’s also a small difference in PH tolerance – discus fish will tolerate a PH between 6 and 7, while Oscar fish will tolerate PH between 6 and 8.

Diet and Feeding

In terms of diet, there are some minor differences between the two. Discus fish will primarily prefer a plant-based diet, while Oscar fish are omnivores and will eat almost anything they get as food.

Although discus fish are omnivores in the wild, they will much more prefer a plant-based diet to a meaty diet. They will only eat meats if there are no other types of food available.

In most cases, they will feed on algae and plant matter that collects in their habitat.

On the other hand, Oscar fish are omnivores, although they will also prefer a meatier diet. They will likely eat other small fish in the tank, but they also prey on small insects, invertebrates, larvae, and other live foods.

Occasionally, they will eat plant matter and similar foods, but you will do better if you feed them meats.

Schooling Fish

Another key difference between the two is that the discus fish are schooling fish. They will prefer to live in groups of at least five, which can be done as long as the tank is big enough.

On the other hand, Oscar fish will prefer to live alone, and you might have a lot of success by keeping them alone.

They are not the greatest tank mate in the world. They can live with other Oscar fish, but big considerations need to be made before you consider such a setup.


To conclude, discus fish and Oscar fish are not great tank mates. There are many differences that would prevent them from living together successfully.

The biggest problem here is that Oscar fish are just too aggressive for discus fish, which are timider and more peaceful.

And as Oscar fish are larger than discus fish, they would get intimidated easily and might not be able to sustain the attacks of Oscar fish.

There are also differences in their diet, behavior, schooling preferences, as well as water requirements. These are all the reasons why these two fish are not great tank mates for each other.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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