Oscars Fighting: How Can You Stop It?

Oscars fight, it’s what they do. Not all of them fight, but a good portion of oscars are just naturally quarrelsome. In nature oscars are territorial. In the wild their territory will be much bigger than the tanks the vast majority of us can provide.

But, like I say, not all oscars fight—some are nice as pie and will even swim together in non-pair groups. Check Google image search, you can find awesome photos of oscars swimming together in groups of three or more!

That’s because every fish has a different personality, and none more so than cichlids. And oscars are cichlids, remember. If you raise a group together from very small juveniles to adults, there’s a decent chance they’ll live peacefully. But, cichlids being mercurial fish, you might find one day one of your group decides it’s fighting time!

how do you stop oscars fighting
By Jón Helgi Jónsson (Amything), CC BY-SA 3.0,
Oscars can be pretty mean fish sometimes. How do you stop them fighting?

Then, that’s that, you’ve got a big problem on your hands.

Oscars can bully each other to death if you’re not careful. So, it’s best to address any excessive fighting between your fish. Now, notice I say “excessive”—this is because a little bit of lip locking and chasing isn’t necessarily the end of the world. That’s not a big deal if it never goes beyond that. However, when you see chunks missing from your oscars, then it’s time to act, and act quickly.

So, with oscars fighting, you have a few solutions you can consider.

Bigger Tank Might Help, But Isn’t The Best Solution

This is something you’ll hear a lot of people tell you.

“Well, you just gotta give them more space so they can stay out of each other’s way.”

Frankly, I don’t think that advice is particularly helpful in most cases. That is because—as I mentioned in the intro—you almost certainly won’t be able to give your oscars big enough tanks that they can each have their own territory. The dominant oscar will simply take the majority of the aquarium’s space for his or herself and pin the other fish in the far corner of the that space.

And that point about pinning a fish into a corner is key.

Your dominant oscar just wants to chase the other guys in the tank away; it wants to establish a territory to feed and breed inside of. But, from your dominant oscar’s perspective, no matter how much he or she chases the other oscar away, it just never gets the message and leaves! Your dominant oscar can always see the submissive oscar at the other end of the tank.

Now, for us humans, we have the capacity to understand that the weaker oscar simply cannot escape the confines of its aquarium. So, it’s condemned to be a victim of bullying probably until it dies of injuries.

Hiding Spots – Out Of Sight, Out Of Mind

So, if you read the previous section you’ll remember that I said a bigger tank won’t necessarily help. This is because your oscars (crucially) will still be able to see each other.

In this section, I want to explain ways you can keep multiple oscars in the same tank while giving them opportunities to escape each other’s view!

Even the smartest fish doesn’t really compare to human intelligence. Cichlids are intelligent by fish standards. But in my experience, even they are subject to the “out of sight, out of mind” rule.

Using hiding spots with cichlids is a time-tested technique to keep aggressive and territorial cichlids in the same tank. This is because, typically, a cichlid will only chase away a threat until said threat has disappeared from sight.

terracotta pots
Terracotta pots are a good way to give fish places to hide from each other.

Therefore, you can use decoration in your tank to create hiding spots for fish. A bullied fish can then easily retreat to a hiding spot and avoid being injured by the aggressor.

My favorite aggression reducing tool for large cichlids like oscars is the terracotta flowerpot. I like them because you can get very large ones. Additionally, you can use them horizontally or vertically, and you can easily break them into pieces.

Rearrange The Furniture i.e. “Re-Scape” The Tank!

Also, remember that oscars—like most cichlids—are going to center their territory around a breeding spot.

So, if your tank has a good breeding spot—like a large, flat stone—then a pair might choose that to be the center of their territory. If they do, they will then fight off any other fish (not just oscars) that come near that spot.

As a result, you might need to look at your oscar tank and see is/are your aggressive oscar(s) defending a particular spot of the tank? If so, consider taking all the ornaments and fish out of the tank, and rearranging the whole thing. That way, when you reintroduce the fish, they won’t feel confident and “at home”.

After a good rearrange in an aquarium, cichlid aggression can be significantly reduced. Although, as fish begin to establish their territories again, you might find fighting in your oscars returns.

Target Fish / Dither Fish

Cichlids, especially breeding pairs, sometimes need to take their aggression out on something. And if they’re the only fish in the tank, then they’ll take that aggression out on each other.

So consider adding other fish to the tank that are big enough and fast enough to escape your cichlid’s attention. Schooling fish are best as that way, generally, your oscar won’t single one fish out for harassment, but will instead divide its attention between the school.

Tinfoil barbs
By Ginkgo100 at the English-language Wikipedia, CC BY-SA 3.0,
Tinfoil barbs are good target fish to help stop oscars from fighting among themselves.

Good examples of larger schooling fish that are readily available in the aquarium hobby are tinfoil barbs, bala sharks, and silver dollars. Out of those, I tend to go for tinfoil barbs as my favorite for the job.

Be aware that while your oscar might be your favorite fish, the target fish you buy are living creatures too. So, keep an eye on their health and watch to make sure your oscars aren’t catching them and hurting them.

Drastic Solutions For Fighting Oscars

If none of the above works and your oscars are still fighting, then it might be time to consider some more drastic solutions. You might not like some of these options. However, I would encourage you to consider them if your oscars are suffering as a result of their fighting.

Get Another Aquarium To Keep Your Oscars Apart

I appreciate that not everybody is like me, not everybody wants to spend every last penny on more fish tanks and more fish. But, a great option to stop oscars fighting is to just put them in different aquariums!

It’s as simple as that.

Young oscars are less prone to fighting compared to their sexually mature counterparts.

If you’re like me and live in the US, keep an eye out for sales at the big box stores like PetSmart and Petco. You can often buy brand new tanks from them at low prices! Another way to get an additional aquarium at a cut price is to buy one used. Check Craigslist, Offer Up, Let Go, and Facebook Marketplace—they’re all great platforms to find a good deal on a used fish tank.

Beware: some people think their old aquarium is worth may more than it is. I’ve seen sellers listing fish tanks for more than they would cost brand new! So, be sure to compare the new prices before buying used!

Use A Tank Divider To Stop Your Oscars Fighting

A tank divider is a good solution if you have two oscars in a decent sized tank and don’t want another aquarium in your home.

Lighting diffuser (sometimes known as egg create) is commonly available at DIY stores and makes an excellent aquarium divider. Be careful though, you’ll need a good way to secure it in your tank because oscars are strong and may push it over if it isn’t secured well.

egg crate lighting diffuser can be used to keep fighting oscars apart
Egg crate / lighting diffuser can be used to keep fighting oscars apart.

Some fishkeepers use zip ties and suction cups to secure an egg crate divider and that works quite well. But, in my experience, suction cups are never 100% reliable. So, I like to use a couple of big rocks either side of the divider to help hold it in place in case some of the suction cups come loose.

Re-Home Your Fighting Oscars

I love my fish, and if you’re reading this long article about oscars, then I’m guessing you love your fish too? So, it can be a hard choice to come to sometimes, but… sometimes it’s just best for our fish if we re-home them.

There are good ways and bad ways to re-home your fish.

The key to re-homing your fish is getting your fish into the hands of another experienced fishkeeper who cares about fish as much as you do.

Dropping your fish off at a random pet store might not be the best way to secure its future! Notice I say “random” because not all pet stores or fish stores represent a bad place to re-home your fish. Some fish stores are amazing and ran by caring and passionate hobbyists. Others, not so much.

So, before you choose a store to drop your fish off at, try to do a bit of research about the store. A good place to start is online reviews; see if people have good things or bad things to say about the place. Also, you can begin a conversation with the staff to discretely assess their knowledge of and passion for the hobby.

aquarium societies and clubs
Making connections at aquarium societies and clubs is a great way to find fishkeepers to re-home your fish with.

Better than dropping the fish off at a store though, is finding another fishkeeper directly! The best way, I think, to connect with passionate hobbyists in your area is to join Facebook groups, Reddit forums, and (old school) local aquarium societies and clubs.


Reading this article might make you think that oscars are ruthless fighting machines that never give up until everything in their tank is dead. And sure, that can be true for some individuals. In my experience though, oscars are actually pretty mellow compared to Central American and African Cichlids (especially if you raise them together). So, don’t be put off keeping oscars, because they’re awesome!

guide oscar tank mates
Additional Reading
Ever Heard Of Short Body Oscars? Check Them Out!
Recommended Products (Affiliate Links)

Thanks for reading this article. I really hope it’s helped you with your oscars. Please consider checking out some of the links below. They’re Amaazon affiliate links, so if you do make an Amazon purchase via one of my links I get a little kick back at no cost to you! Also, I only recommend products that I use myself and that I think are absolutely top quality.