How to Set Up an Oscar Tank?

If you are looking to set up a tank for your Oscar fish, I am happy to tell you that it’s not rocket science. This piece is going to describe how to set up a sublime Oscar fish tank. 

How exactly does one set up a good Oscar fish tank? There are many things that may come to mind. The answer to that question is simple. You set up a good Oscar fish tank by figuring out what an Oscar fish needs.

Basically, the things to consider are;

  • Temperature
  • Filtration
  • Size
  • Substrates
  • Bubbles
  • Lights
  • Decor
  • Plants etc…

Oscar fish have specific shelter needs and there are specific ways to fulfil those specific needs. The paragraphs below are going to go into in-depth discussion of each of these needs and how you can meet them in the easiest and fastest way. 

Now don’t you worry, owning an Oscar fish isn’t that much of an issue. Setting them up apporiately can be very easy too. So long as you understand what your fish needs and how to make sure they get it. 

What an Oscar fish needs based on their wild life preferences

In the wild, Oscar fish originate in the Amazonian rivers. They are freshwater water fish that can grow as long as 18 inches and may weigh more than three pounds, when they grow to full maturity.

They are native to lush aquatic vegetation. Warm fast flowing waters, and they are well known for their lack of tolerance for cool waters. 

Since these fish are freshwater fish in fast moving warm waters… whatever sort of water they are kept when outside their natural habitat should be the same as the sort of conditions they are coming from or at least something close to it.

There are other parameters that may determine what sort choices you need to make for your Oscar when it has to do with accomodations. Here are a few things to consider when choosing a tank for your fish.

Will you be keeping multiple fish?

It is very important ro answer a question like this before you make your choice of fish tank because it can inform how big a tank you need to get. If you intend on keeping multiple fish either of the same or different species, you will need to get a bigger tank. 

The reason for this is that Oscar fish are very territorial and they will often attack other fish who venture into their personal space. Now the concept and idea of personal space may change drastically when you keep two or more fish in a tank that really shouldn’t hold more than one of such. 

The Oscar fish may attack or even kill and eat other fish who come into their space. In order to prevent you fish from killing, maiming or eating each other, you will have to get them a tank that will not cramp them together. 

Will you be breeding your Oscar fish?

Now I am sure you’re wondering what breeding and fish tanks have in common. The thing is that if you decide to breed fish, you will need not just the big tank for both the male and female fish, you also need a small tank to evacuate the baby fish into once they are hatched.

This needs to be done to prevent the big fish from eating their own fry due to stress or any other weird reason parent animals eat their own offsprings. It is also important to make sure that the mom and dad have a big enough tank for their pre fertilization love fight. 

The bigger the tank, the bigger your filter

Your filter needs to be in tandem with your tank. You can’t use a small capacity filter for a big capacity tank. Filter is a very important part of aquarium care  and if your filter is not strong enough to handle the workload of it’s tank, you might as well not have a filter at all. 

Now to be clear, you can’t afford to not have a filter. Your fish wellbeing and even life or death depends on this and it is non negotiable. So you need to get the right filter for the right tank.

How to go about setting up my Aquarium?

Having discussed the things to consider when choosing and setting up your tank, the following paragraphs will be dedicated to discussing the area you should take when setting up your aquarium.

Choose your tank size

The first thing to do is to use the above considerations to choose the tank size that will best serve your needs. 

Oscar fish often grow to 10 inches  length or more. The basic size that is  recommended for Aquarium that will house one Oscar is about 55 gallons. A 75-gallon tank is however considered the best for a fully grown Oscar fish.

If you choose a tank that is too small for your Oscar, you may have one of the following problems. 

Problems of small tank

  • The water will get polluted easily and it  may be difficult to maintain good water quality.
  • Your fish may not get enough swim space and exercise. This could lead to constipation and fatigue.
  • Your fish may injure himself and such injuries may not heal properly because of the poor water condition that was described above. 

Choose a good and quality filter

Oscars are big feeders. Now you should consider that they poop as much as they eat. This will most likely result in a large waste collection and this a large bioload. You will therefore need a good filter so as to maintain a good water condition for your fish. 

A good water filter will help keep your fish happy because the water will be clean and healthy for them. A good water filter may also be the major difference between illness and health for your fish.

Problems of bad water filter 

  • The water will become toxic very fast.
  • You’ll need to change the water more often as a result. 
  • Bad pH or bad water condition could cause illnesses and disease.
  • At some level, bad water conditions as a result of bad filter could kill your fish.

Get the appropriate fixtures and decor

You may want to zas things up by providing your Oscar with some decor for their aquarium. The aim is to make the tank as close to nature as possible. But decors aren’t the only things your fish tank wi need. You will also need fixtures like heaters and substrates. 

More on this will be discussed in the subsequent paragraphs.

Setting up the best Aquarium for your Oscar

The process of setting up an Oscar fish tank isn’t any different from the way you set up the tank for any other freshwater water specie. You can follow the following steps. 

Step 1

Wash all your equipment and ensure the ornaments are well washed and ready for installation. Depending on whether you are using an  under-gravel filter, this is the time to install it on the tank. You should aim for a filter depth of 3-5 inches below the substrate. If your substrate is sand as opposed to gravel, you may want to use a pre-filter 

This will prevent sand from entering your filter and destroying it.

Step 2

Condition the tank water

The next thing to do is to condition your tank water. You can get this done by letting tap water sit for 24 hours. You could also use a water conditioner to  rid the water of contaminants.

Step 3

Pour the water into the tank

Now you should gently lower the water into the tank. Try as much as possible to not disrupt the substrate. This is especially important if the substrate you used is sand.

One easy way to get this done is to place a clean empty bowl in the tank and the. Slowly pour the water into the bowl as opposed to just turning it into the tank.

Step 4

Add ornaments

When you pour the water to half filled level, this is the time to install your ornaments. It is important to know that Oscar fish are very naughty and can be destructive. They live to dig their substrates. This means that they may pull up their plants and dig up their ornaments.

Take time to secure the ornaments on the tank properly to avoid your fish pulling them up or swallowing them. You should also try not to overdo the decorations thing. Too much of ornament may restrict the movement of the fish.

Step 5

Lid the tank

The thing is, Oscars are known jumpers and escape artists. You don’t want to leave your Oscar fish tank lidless. If they don’t jump themselves, they will make other fish in the tank jump. This can be harmful to them in the long run so please get a lid for your Oscar.

Step 6

Temperature control

One very unique thing about Oscars is their need for specific temperature levels. Due to the fact that they are used to amazon rivers that are warm,  these beautiful fish do not tolerate cooler waters very well. They are highly sensitive to temperature fluctuations.

You will need to use an aquarium thermometer so as to keep easy track of the Oscar fish tank’s temperature. The ideal temperature for Oscars range between 74-81 °F, and their most proper temperature is around 77 °F.

One of the ways to ensure that your aquarium remains in a particular temperature level is to use an aquarium water heater to keep the water warm.

You can get an in line heater as this will help keep the water heated in the filter as it goes back into the tank.

You should however get only shatter proof submersible heaters as Oscar fish can be quite destructive.

Ideal Tank Mates

Oscar fish are rather large fish. Because of this, it is impossible that you choose their tank mates carefully. It is important to know right away that Oscar fish do not absolutely have to have tank mates. It is mostly your own need to have more fish that will make you get them.

Don’t get your Oscar a snack tank mate

Oscar fish do very well on their own. In fact, they may even be better off on their own. If you do buy tank mates for you Oscar however… make sure that you are not juts getting him a snack. Basically any fish that can fit in your Oscars mouth is a potential snack.

The mouth of an Oscar will take any animal that is smaller than 5 inches.

Shy mates are no mates either

You could also try not to get your Oscar fish a shy or timid tank mate. This is because a shy or timid tankmate will be susceptible to your Oscars bullying. And we all know that Oscars are born bullies. 

Your Oscar will likely chase the shy fish around the tank and stress them out. They may nudge or bite the tank mate to the point of despair and stress.

Bottom dwellers rock

A bottom dwellers is probably a good idea because they are very likely to stay out of your Oscars way. This is because Oscars are to mid level dwellers.

Specific fish to consider

Some of the fish that fit the criteria above and would likely be able to co exist with your Oscar fish include but are to 

  • Catfish, 
  • Silver Dollar fish,
  • Firemouth cichlids, 
  • Convict cichlids,
  • Blue acara.


Larger cichlids like Texas cichlid and terrors are very likely to be aggressive and cause problems in the tank so you will do well to avoid them too.

There are no specific lighting requirements for Oscars. You may even choose to not have any sort of lighting. You will however need a lighting device if the plant in your tank is a live plant. 

Oscars are known to love dark and murky areas in the wild. They therefore will not mind very much if you choose to keep their tank just so.

Do Oscar fish need Bubbles?

Not necessarily. But the filtration system will probably make bubbles anyways

Do Oscar fish need Hiding Places?

Oscar fish can be very playful and funny. They are also avid escape artistes and thus will definitely enjoy hiding places. So Yes. They need to be able to play and hide. But they may particularly need places to hide if they are breeding.

It is however important to not have too many things in the tank at once. It may make it difficult for the fish to swim around or for you to be keep the tank clean. 

Can I put an Oscar Fish in an outside pond/tank?

No. You should not even think of this. You cannot control the weather and temperature outside of a tank. Except you are taking your Oscar to an Amazonian rivers in which case you would be reintroducing them to their natural habitat, you should not put them in outside ponds. 

Do Oscar fish need sand?

Not particularly. They however need some form of substrate. This could be sand or gravel. Just know that sand may be easy for them to invest and therefore more likely to cause impaction or constipation.