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Best Tankmates for Oscar Fish

Oscars are a type of South American cichlid found primarily in the Amazon River in areas with a strong current. They’re large, formidable fish with big mouths, known for their ‘tiger ‘markings and hostile nature. If you have (or are thinking of keeping) Oscar fish, you may be wondering which fish make the best tankmates? Or, do Oscar fish get along with other fish?

The best tankmates for Oscar fish are other Oscars. This species is known to be both aggressive and territorial in captivity and will thrive in pairs or small groups of up to 5 in an extra-large, species-only aquarium. If you want to keep Oscars in a community tank, consider fish that are of similar size.

Now that you know Oscar fish do best with others of their kind in a contained environment, let’s explore this topic in more detail. Together we’ll learn whether Oscars can live with other species like goldfish, koi fish, arowanas, and/or piranhas. We’ll also uncover if Oscars can be housed with different types of South American cichlids and if it’s okay to keep them with invertebrates such as crab and shrimp.

So, if you’re ready to learn more about tankmates for Oscar fish and how to properly care for them in captivity, then let’s begin!

Can Oscar Fish Live with Each Other?

Oscar fish are sociable and typically live peacefully with others of their kind in captivity. They do best in mated pairs or small groups of up to 5 fish in an extra-large, species-only aquarium. Keeping 3 Oscars isn’t recommended as two will likely pair up and harass the odd one out. If you prefer to keep just a single Oscar fish, then ensure the other species sharing the tank are of like size and temperament.

You can, however, house 3 females together if you don’t want your fish to reproduce. Choosing only females will be difficult though, since Oscar fish are monomorphic, meaning males and females look exactly alike. You can also prevent Oscars from spawning by altering the water conditions to make the environment less conducive to spawning.

Can Oscar Fish Live with Goldfish?

Oscar fish may be able to live with goldfish in a huge aquatic environment like a 1000+ gallon pond. That said, Oscars are omnivorous, predatory fish. Anything that fits into an Oscar’s mouth is fair game and likely to be eaten – including goldfish. To prevent this, you must provide a lot of space for Oscars and keep them well-fed. Since goldfish can reproduce rapidly, Oscars will help prevent overpopulation.

Can Oscar Fish Live with Koi Fish?

You may be able to keep koi fish with Oscars, provided they’re of similar size and housed in a big, pond-like environment. Juvenile koi fish will be viewed as potential prey for omnivorous Oscar fish. If you don’t keep your Oscars well-fed and in an extra-large aquatic environment with lots of hiding places, your kois will be at risk. Like goldfish, kois spawn easily so Oscars can keep them from overpopulating.

Oscar fish in a community tank

Can Oscar Fish Live with Algae Eaters?

Oscar fish can live amicably with algae eaters in captivity. Large, bottom-dwelling fish like plecos and loaches will do fine with Oscars since each species occupies a different area in the tank – Oscars prefer to swim in the top half. Oscars are known to be ‘lazy’ feeders and will eat whatever meal comes easiest. Therefore, if you keep them well fed, they’re of no threat to suckermouth catfish or clown loaches.

Can Oscar Fish Live with Arowanas?

Oscars can live with like-sized fish such as arowanas in an extra-large tank – provided you keep them together as juveniles so they can grow up together. It’s not recommended that you keep Oscars with Australian arowanas as they’re just too aggressive. Instead, opt for silver arowanas that are less hostile. When choosing tankmates for Oscars, consider species that are non-aggressive and roughly the same.

Can Oscar Fish Live with Piranhas?

Since both Oscars and piranhas are indigenous to the Amazon River, they can live together in an extra-large, highly circulated tank. That said, it’s important to note that piranhas have voracious appetites and may attack juvenile Oscars if not given enough food. To prevent this, make sure your Oscars are bigger than your piranhas and keep your fish well-fed in an extra-large, heavily rooted planted aquarium.

Can Oscar Fish Live with Silver Dollars?

Silver dollars can live amicably with Oscars in captivity for two reasons: one, they’re big enough not to be seen as food for Oscar fish. Two, they act as ‘dither’ fish – meaning they swim about freely in the middle of the tank which signals to Oscars that the tank is safe (no predators around). A small group of silver dollars will not only hold their own against aggressive Oscars but help keep their hostility at bay.

Can Oscar Fish Live with Cichlids?

Oscar fish will do well with other types of South American cichlids, provided they’re of like size and temperament. Since they all come from the same aquatic source (blackwater streams, creeks, and rivers of the Amazon basin), they can co-exist in captivity under the correct water parameters. Think black convict, blood parrot, blue acara, firemouth, green terror, Jack Dempsey, jewel, and jaguar cichlids.

Can Oscar Fish Live with Sharks?

Oscar fish can live with bala, rainbow, and red tail sharks in captivity, so long as the tank is big enough to prevent them from becoming aggressive and/or territorial. Red tail sharks (which aren’t sharks but a type of carp) will become hostile if they don’t have plenty of space therefore, an extra-large, 120-gallon aquarium is required. They also like to swim near the bottom of the tank and out of the way of Oscars.

Red-tail shark

Can Oscar Fish Live with Crustaceans?

Oscar fish are omnivorous and predatory by nature. They’ll eat anything small enough to fit into their mouths, including crab and shrimp. The only crustaceans that can safely live with Oscars are those that are too big for them to devour. Consider invertebrates that are at least 4 inches in size and ensure your Oscars well-fed to prevent them form attacking tankmates.

Final Thoughts

In summation, the best tankmates for Oscar fish are other Oscars. As a type of schooling fish, Oscars like the company of their own kind, especially when young. Once they reach sexual maturity, they typically pair up. With advancing age, they tend to live more solitary lives. While best kept in a species-only tank, they can also live with different types of South American cichlids and other peaceful fish of similar size.

I trust this article has been of help to you in determining which aquatic creatures to house with Oscars. Thanks for reading and good luck with your aquarist hobby!

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