Oscar Fish Guide

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While not the most popular fish at the pet store, the Oscar fish is a favorite among fish keepers for their variety of beautiful colors and their bountiful personalities.

However, like other cichlids, Oscars tend to run on the aggressive side and should not be considered as an addition to a crowded or small aquarium.

These fish are not suitable for the beginner aquarist.

For those unaware of who or what the Oscar fish is, this particular fish might seem like a good fit when you find them at the store, considering the fact they’re sold at about 1-2 inches of length. But they definitely don’t stay that small forever, growing up to be 11-12 inches long on average.

When bringing an Oscar fish home, know that they can live for 10 to 13 years – a longer lifespan than most dogs!

So are they the right choice for you, and if yes, what do you need to know? We have you covered.

Oscar Fish: Appearance

While many fish can be recognized by a single color or slight variations, Oscar fish are extremely diverse in their color and patterns.

Solid colors can range from startling yellows to brilliant reds to a midnight black. Albino Oscar fish are also available, but are often harder to find.

Some with certain color patterns are called Tiger Oscars, for their adorable little stripes.

tiger oscar fish
By Mazapura (CC BY-SA 3.0 licence)

The red Tiger Oscar looks like they’re magma incarnate with how their red and orange scales contrast with the black scales.

The white Tiger Oscar looks like an inverted version of the red one, with the similar orange pattern on a white background instead.

The blue Tiger Oscars’ scales make them look like contrasting waves of the water.

Oscar Fish: Personality

Oscars are a bit different than most fish, their appearance and intelligence making them truly unique for owners and hobbyists alike.


All cichlids, the family that the Oscars belong to, are known to be both aggressive and intelligent.

Some owners have reported that their fish can recognize them and that they will show excited behaviors such as wagging their tail and quickly swimming back and forth.

Some owners have reported their fish’s aptitude for playing; if you place a ping pong ball in the water, Oscars are known to swim up and interact with the floating ball.

Not many people can claim they do more with their fish than just stare at it!


Oscars are often described as having a great or big personality.

Often times, this simply means your fish does not portray simple characteristics and will have a well-rounded idea of what they like or dislike. They’ve been described as having the personality of dogs: loving of their owners and easily excitable.

In some cases, too excitable, considering the fact some owners have reported their Oscars nearly jumping out of their tanks.

Simply put, you won’t have a big chance of getting two Oscar fish who act alike.

baby oscar fish
Baby oscar fish (By Prakash Chakraborty CC BY-SA 3.0 licence)


While they’re rarely known to actually injure their owners in any kind of noteworthy capacity, some Oscar fish have shown to become aggressive when their tank is being cleaned.

Aggressive behavior in Oscar is usually demonstrated by opening their mouth as far as they can while flaring their gills in an attempt to look bigger. Keep an eye out for this behavior when putting your hand into their tank.

They may in some cases bite, but considering how small their mouth and teeth are, this isn’t considered dangerous or severely painful. If your Oscar fish attacks you while you clean their tank, it’s possible that they may not be accepting of tank mates.


The average Oscar fish price is around $12 to $20, though prices may change due to availability and type or color.

These fish are often given away for free, as some will buy these fish when they’re small and not wish to take care of a bigger fish.

Oscar Fish Care

First and foremost, you need to know how to take care of a new fish before you bring them home, so as to avoid being overwhelmed by their current and future needs.

Tank Requirements

As an absolute minimum requirement, you should have a 55-gallon tank for your Oscar fish.

Buying a smaller tank when you get them and a bigger tank down the road for when they “get bigger” isn’t advised due to their rapid growth to maturation. If you have the space, dedicate a 75-gallon tank or even larger to your Oscar fish.

oscar fish food

Water Requirements

Oscar fish are freshwater, meaning that you’ll have add a chlorine neutralizer tablet if your faucet water contains chlorine.

Water temperature should be 77° F (23° C) and should have little fluctuation. Keep out of direct sunlight to avoid these fluctuations, as your Oscar fish will be sensitive to the changes.

While Oscar fish are hardy enough to tolerate some changes of pH or water hardness, the pH level should be kept at or around 7 and the water hardness within the range of 5dH to 10dH.

Considering the tank to house your Oscar should be large, we’d highly recommend buying a large canister filter to keep the water quality as high as possible.

Oscar Fish Tank Set-Up

All decorations and equipment should be washed and cleaned before they go into the tank.

Condition your tank water by letting tap water sit for 24 hours or by using water conditioner.

Put in 3-5 inches of substrate or sand in your tank, and then gently pour in your conditioned water.

After that, you can add all your decorations and equipment, but do not plug in or start the equipment until you’ve decorated the tank.

Considering the size of the Oscar fish, try not to fill your tank to the brim.

Last is to add your fish. Properly acclimate them to the temperature of the tank’s water by setting them in the tank while still inside their bag. This will give them the chance to adjust slowly instead of being dropped in suddenly.

Here’s a great look at the setup of a successful Oscar tank:

Tank Maintenance

Because of how much the Oscar fish eats, the bioload in the tank will be big enough on its own before you even consider adding any other fish.

You’ll need a good filter to keep the water clean.

For extra help on keeping the water clean, use both a canister filter and a hang-on-back filter. The smaller your tank is, the harder it may be to keep the water at an acceptable water quality level.

Oscar Fish Food

It’s important to an Oscar fish to have a balanced diet of commercial granules, frozen worms, brine shrimp, and beef liver, but it’s very healthy for that diet to be supplemented with live snacks.

All live fish should be considered carefully due to their ability to pass on diseases or parasites as well as disrupting the fat ratio in your Oscar’s diet. Live crickets or bloodworms are a good substitute to live fish.

Oscar Tank Mates

While Oscar fish aren’t vicious killers that you need to keep separate from all other fish to avoid any unnecessary deaths, they are still semi-aggressive.

This means that thought has to go into who you pair them with.

The first thing you need to understand is that adding any tank mates – no matter the size – will require a bigger tank than the minimal 55-gallon.

Providing more space can prevent any aggressive behavior brought on by limited space, though it won’t prevent aggressive behavior or actions due to individual personalities and/or incompatible species.

oscar fish care
By Daniella Vereeken (CC BY 2.0 licence)

Most fish will not be compatible with the Oscar fish, especially smaller ones.

Still, there are a few good tank mates worth considering…

Other Oscar Fish

If you’re considering getting two Oscar fish and only using one tank, keep in mind that it’s up in the air whether or not your two fish will get along.

Get a tank no smaller than 125-gallons to minimize the chance of the two becoming aggressive and attacking each other.

This doesn’t offer guarantees of friendship, and in fact, the possibility of the two Oscars becoming aggressive towards each other increases as time goes on, as they favor solitude as they age.

It’s strongly recommended that you do not attempt to house three Oscar fish together.

Black Convict

Rather resilient at six inches long, this cichlid is a safe choice to be a tank mate for your Oscar. They’re aggressive enough to endure living with a larger fish but tough enough in case a chase breaks out between the two.

When adding a convict, use a 75-gallon tank and add a rock cave or a few pieces of wood for a bit of cover.


Like the Oscar, severums are a semi-aggressive cichlid but tend to be rather calm, so they shouldn’t bother your Oscar so long as you upgrade to a 75-gallon tank. They’re in similar size to the Oscar, usually growing to 12 inches at full maturity.

They make an excellent choice as a tank mate for your Oscar.


The firemouth is far from combative and will avoid confrontation with an Oscar.

This one is fairly small cichlid at eight inches long, but will stand up for itself if confrontation happens.

Be sure to get at least a 75-gallon tank when housing these two together.

oscar fish facts
By Ashish Ghosh (CC BY-SA 3.0 licence)

Featherfin Syno

Consider adding the featherfin syno to at 75-gallon tank to be your Oscar’s tank mate.

They’re just a few inches smaller than the average Oscar, but are peaceful, making this catfish a compatible tank mate.

Silver Dollar

Though not a type of cichlid, a handful of silver dollars would make for a good tank mate for your Oscar.

Unlike your Oscar, however, silver dollars are not comfortable by themselves and should have at least two other silver dollars for company.

For three silver dollars and one Oscar, use a 75-gallon tank.

Do you own an Oscar fish?


Featured image is by Jón Helgi Jónsson (Amything) (CC BY-SA 2.5 licence)

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