All About Oscar Fish-The Easy Guide

Fish, fish, and more fish! There are so many choices to make when you are contemplating an aquarium, whether you are a beginner or a novice aquarist. But do you want little guppies, goldfish, rainbow fish, or do you want something bigger? Are you getting the aquarium for your child(ren) so they can have their first pet, or are you purchasing it for you? If you are looking for yourself, why not go big? Make a HUGE statement. Have a real centerpiece or focal point for your guests and family to ohh and ahh over. Let’s get an Oscar!!

Oscar’s are fish that will definitely make a statement and draw attention when someone walks into your home. You will need at least a 55 gallon aquarium for your Oscar. They are smart fish, semi aggressive, and temperamental. But, over time, they can recognize their owner.

Owners say they are very intelligent. Oscars are also stunning to look at. These fish can reach up to 18 inches long and up to 3 ½ pounds. They need a good amount of swimming room when they are fully grown.

Now that we have your attention and have peaked your curiosity about the Oscar fish, let’s delve into all there is to know about them. I will discuss life-span, habitat, best tank set-up, and how to care for your Oscar. So, if you are ready to learn about this hardy, intelligent fish, then let’s jump into it.

History and Life Span of Oscars

These fish are a species of the cichlid family. Normally the Oscar resides in tropical South America and are sometimes found in fish markets for sale as food. In the United States and Europe they are a popular fish to have in your aquarium. Oscar fish have also been introduced in Australia, India, and China.

The Oscar can grow to be between 15-18 inches long and again, up to 3 ½ pounds. So, with the rule that we have discussed before; 2 gallons of water per inch of fish, you should be able to have an Oscar in a 40-gallon tank. But we will discuss more on that later. An Oscar can live to be between 10-20 years old.

The wild Oscar are dark colored with yellow spots, that are ring shaped, on their dorsal fin and sometimes on the tail fin. The Oscars are able to quickly change their colors if they feel they are in danger, or to stand their ground as they are very territorial. A juvenile Oscar is striped with white and orange bands and has spotted heads. 

Types of Oscar Fish

There are several different types of Oscar that you can choose for an aquarium. We will describe a few and give you the names of the others. Initially, there were only 3 types of Oscars; Red, Albino, and Tiger. 

All of the variations are because of cross-breeding the 3 original types. Now there are over 10 types of Oscar fish, and they are all stunning in their own way and magnificent to look at.

Tiger Oscar is the most popular type. Their colors resemble that of a tiger. Sometimes the color pattern is only close to the tail and other times it covers most of the body. The Tiger Oscar is anywhere from 12-15 inches long. 

My personal favorite is a crossbreed. It is the Blue Oscar. Their entire body is different gorgeous shades of blue. The dark blue lining on their scales makes them really stand out. Some of the Blue Oscars have just a little bit of yellow/orange meshing with the blue.

The Albino Oscar is all white, except for it’s pattern. It is an orange/red intertwined pattern normally found closer to the tail. Some will have a small pattern up by their fin. No two patterns are exactly alike, making the Albino Oscar very unique. 

The other Oscars that are out there; Black Oscar, Florida Oscar, White Oscar, Green Oscar, Lemon Oscar, and Veil Tail Oscar. All would look amazing swimming around in your aquarium.

You Can See the Video Below 12 Amazing Oscar Varieties

Video from Hatty Aquarium YouTube Channel

Caring for Your Oscar

It is suggested that Oscars should only be taken care of by experienced fish keepers because of their possible aggressions, social behaviors, and intelligence. But, if you do your homework I believe that anyone can take care of an Oscar. They can be very temperamental and therefore it is hard to find a suitable tank mate. So a lot of aquarists recommend not having any. 

Their care level is said to be moderate, they need a minimum 55 gallon tank, and they are omnivorous. So, the rule of 2 gallons per inch of fish doesn’t really apply in this case. They need the extra room to move around, so a 40 gallon is not going to be quite big enough for an Oscar. In your freshwater tank you are going to want to have rocks and at least 2 caves, for your Oscar to hide in.

The Perfect Oscar Tank

It is best if you set up your aquarium as close to their natural habitat as possible. They will feel more at home and relaxed. Their natural habitat in South America is the fresh warm water of the Amazon. The Oscar can not handle acidic water or water that has too much alkaline in it. So you will have to be diligent in checking your water once a week. 

Their natural water flow is fairly strong as most Oscars, as stated above are found in the Amazon. The sunlight is also strong in this area but does lose some of its intensity due to unclean water. At the bottom of your tank, you will need to use a soft substrate and decorate with rocks, bogwood, and vegetation scattered around. They are known to up-root plants and other decorations so you will have to make sure that they are all secured to the bottom.

The perfect substrate for your Oscar is going to be fine-grain sand. Since they like to dig you can not have anything that is course, because it could scratch them up or even cut them open. You are, of course, more than welcome to decorate any way that you like, these are just suggestions and recommendations. Oscars love their hiding places so definitely make sure that you have at least 2 caves in your tank. 

If you choose to use plants, whether live or plastic, make sure they are a hardy plant. This will hopefully ensure that they can withstand any digging and tempers that your Oscar may have. As already stated, just make sure they are secure. You could also look into floating plants. They would at least be safe from the digging. 

As far as temperature and chemical levels go; your water should be between 74-81 degrees. You want your pH level to be between 6-8 and you need to keep your KH level between 5-10. You don’t really need any special filters, heaters, or lighting. As long as your filter outlet provides enough current to make your Oscar happy and feel as though they are at home in the wild.

Aquarium Size and How Many Oscars Per Tank

 As we stated above, a couple of times, because of the size of the Oscar you need at least a 55 gallon tank. Personally, I would go with a 75 gallon. This is taking the plants, rocks, and other decorations into consideration.

This will still leave them plenty of room to swim around and be comfortable. 1 Oscar is said to be happy in a 55 gallon and that you just need to add 20-30 gallons for a second Oscar. So basically a 75-85 gallon tank for 2 Oscars. Again, I would err on the side of caution and go with a 100-gallon tank if I were going to house 2 Oscars.

As stated, quickly above, they suggest no tank mates for Oscars because of their territorial attitude and aggression. If you are set on having a tank mate then you need to make sure that the other fish is just as big, if not bigger than the Oscar.

They also need to be passive but able to defend themselves if need be. If you try putting smaller fish in the tank, they will eventually be dinner for your Oscar.

Here are just a handful of fish that would work as a tank mate:

  • Arowanas
  • Firemouth Cichlids
  • Green Terrors
  • Jack Dempseys
  • Jaguar Cichlids

There are a few others, mostly from the Cichlid family. They are the obvious tank choice for a tank mate for Oscars because they can hold their own if attacked.

Aquarium Maintenance

Since the Oscar is a larger fish, you know that there is going to be more fish waste. This causes more ammonia and nitrites in the tank. Unfortunately this is going to mean a little more work for you as far as keeping the aquarium clean.

You can look into getting feeder fish. They will eat the debris and the algae from the tank, although not much, and they are also food for the Oscar. A little help is better than no help when you have a large fish. Just be cautious, any feeder fish brought in could potentially have a disease and in turn will make the Oscar sick.

You are going to have to clean your tank at least once a week, especially if you have 2 Oscars. Their water needs to stay as clean as possible to keep them from getting sick and to prolong their health and life.

A lot of aquarists recommend your pair a canister filter with a HOB filter. It is also suggested that you use an in-line heater. This will link to your canister filter and ensure that the water is heated as it is returned to the tank during filtration. 

Ultimate Filtration System

One avid aquarist recommends the Fluvial Filtration System. The optimal one is the FX6. This is a very powerful canister filter that can efficiently keep a 400 gallon tank clean and clear. Overkill? Maybe! But your Oscar should never get sick and your water will stay clean and clear, which will also make the Oscar very happy. Less stress means less aggression.

The Fluvial has up to 6 stages of filtration and a versatile design that includes; rubber feet, twin out-put nozzles, click-fit valves, and more. It is efficient, quiet, and has an auto-start feature. It also makes changing the water less messy.

This is due to a separate hosing that you will have to purchase. You attach the hosing to the output and the smart pump does the rest. No more carrying buckets of dirty aquarium water across your living room carpet.

Some other features include: 

  • Mechanical, biological, and chemical filter media (which is included)
  • Anti-clog strainer, giving you continuous water flow
  • 21” tall makes it easy to fit under most aquariums
  • Can be used with fresh or saltwater aquariums

Definitely check out this filtration system for your Oscar tank, or any other big fish that you choose to have in your aquarium. It CAN and WILL keep up with the fish waste (for the most part). Definitely look into other options as well.

You want to make sure that you can afford the items that you need. It is not mandatory that you go overboard with the filtration system. Fluvial does have smaller filtration systems that will work just as well for a 55-100 gallon tank.


There is so much more to learn and discuss the Oscar fish. I will be bringing you part 2 in a few short days. For now, remember; no tank mates unless they are other Cichlids, they are intelligent but can be aggressive if they get too stressed, and they are omnivorous. We will cover feeding your Oscar in our second installment, among other things.

So keep an eye out for that. If you are a beginner and do choose to have an Oscar, make sure you do intensive research and homework so that you can properly take care of them. A lot of times Oscars are not cared for properly and do not make it more than 5 years.


I'm passionate about fish pets and love sharing everything I learn about them.

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