How to Set Up Oscar Fish Tank? [2022]

Before you get started, there are a few things to consider.

First, the Oscars can grow very large. If you want to keep an Oscar in a 55-gallon tank, you will need to upgrade to a 75-gallon tank as soon as possible for a large adult oscar.

Second, Oscars are not reef safe and should never be kept with corals or invertebrates like clams or snails.

Thirdly and most importantly: these fish are the worst beginner fish!

Do not purchase an Oscar if this is your first time keeping fish. Instead, choose something else (like guppies) that doesn’t require special equipment or feeding routines.

Oscars are one of the most popular cichlids in the aquarium trade.

Oscar fish are one of the most popular and peaceful cichlids in the aquarium trade and for a good reason.

They’re easy to care for, make great aquarium companions, and adapt well to most environments if given enough space and proper care.

Oscars are generally very peaceful when they’re not breeding. They don’t get aggressive with their tank mates or other fish species unless there’s something in the tank that smells like food—at which point they may become territorial.

They’re also relatively easy to breed! If you need help managing cichlids, read this guide for some expert tips.

They get their name from their ability to change colors.

Do Oscar Fish Have Teeth?
Attack in Oscar Fish Tank

They get their name from their ability to change colors. They can turn from green to brown or orange. This is done for several reasons:

  • To match the environment
  • To show mood following a fight with its tank mate. If you’re tired of watching your fish fighting, here’s how you can stop it.
  • To show health issues (a sick fish will be lighter in color)
  • To show age.

Buying your Oscar

Oscar Fish Tank Setup Guide
Oscar Fish Tank Setup Guide

Before you buy your Oscar and set up your oscar fish tank, consider these tips:

Look for signs of disease

A healthy Oscar will have a vibrant color and be active. It will also be swimming around its tank and interacting with other fish.

Don’t buy it if you think the fish is sick or dying! You may kill your new pet if it has an infection that can spread to other fish in your tank.

Check for signs of stress (and ask about them).

Fish show stress by lying on the bottom or sides of their tanks, breathing very fast from their gills and fins being held down flat against their bodies instead of upright.

Stress can be caused by many factors, such as overcrowding with other fish or being kept in too small a tank for too long, so make sure you know what could happen before bringing home this beautiful creature!

Setting up your tank

Size of your Fish Tank

The tank size is based on how many fish you want to keep. A good rule of thumb is at least 10 gallons per inch of fish, so if you wish to have two nano-size fish that grow to 1 inch long each, a 10-gallon tank will do. Here are my recommendations for the best 10-gallon fish tanks.

If you want a giant aquarium, like 30 inches long and five inches tall, plan on a 55-gallon tank (or even bigger!).

Tank Shape: Traditional Rectangular Style or Hexagonal Style?

It doesn’t matter which one you pick so long as it has plenty of room for all your decorations and accessories.

However, note that most people prefer rectangular shapes because they’re easier to find stands for them than for hexagonal tanks!

Setting up substrate

Fill about half an inch deep with gravel before adding water (about halfway).

This helps with drainage and gives some security from large rocks or other decor items that might fall through cracks between pieces when moved around later during routine maintenance cleaning duties.

At any point, if you feel like you need to finish the tank maintenance quickly, implement these 12 creative hacks to clean your home aquarium.

It also adds coloration if used along with colored sand/substrate mixes such as green dyed kitty litter mixed into medium brown/tan colored gravels.

This combination makes lushly textured tanks aesthetically pleasing visually and tactilely when touched by hands holding netting brushes during maintenance tasks.

Tasks such as cleaning algae off glass surfaces using fine mesh netting brushes are aimed explicitly at removing tough algae deposits.

This is helpful if you want to remove the algae without damaging the delicate and fastest plant life growing within those same areas where said deposits were found growing at the time of cleaning your fish tank.

Choosing a filter

A great place to start is with the tank itself. First, of course, you’ll want to ensure you have enough room for your fish and any decorations you plan on adding, but also ensure that the tank has been adequately cleaned before filling it.

Next, choose a filter based on how many fish you want in your tank:

  • If beginner-level fish keeping is your goal, try one internal power filter or two smaller filters (like an external box filter). If you need help, read this guide to choose the right internal filter for your tank.
  • For more advanced hobbyists who are looking for more than just an aquarium full of water, use three different types of filtration systems: One sizeable external canister filter; A second small box-type canister unit; And finally, another internal power unit (or even just one large power head) if space permits. And if you’re on a limited budget, here’s a list of budget-friendly internal filters to meet all your needs.

Lighting and substrate

How to Choose the Best Aquarium Light
How to Choose the Best Aquarium Light

The substrate you use is an essential part of the setup. The purpose of a substrate is to provide a home for beneficial bacteria and organisms that help maintain the health of your Oscar fish tank. It also provides a place for some of the best and worst plants to grow, giving your Oscar fish tank an attractive appearance.

Substrates should be simple, not too many different types, easy to clean, and non-toxic and inert (non-abrasive). Some examples include:

  • River sand – 2-3 inches deep
  • Marine sand – 2-3 inches deep (some people recommend river sand over marine sand because it’s simpler)
  • Pool filter grade pebbles – 1-2 inches deep


The next thing you need to consider when decorating your Oscar fish tank is what decorations you want to use.

You’ll want to choose decorations that are not sharp, toxic, heavy, or made from materials that will dissolve in the water or rust/corrode.

I would say go with these low-light aquarium plants that require minimal maintenance.

Compatible tank mates

Oscar Tank Mates
Oscar Tank Mates

You should always keep your oscar fish recommended tank mates, such as other cichlids, including angelfish, blood parrots, and rainbows. Oscars can also be held with some non-cichlid fish like tetras or catfish.

However, since Oscars are territorial and aggressive by nature, if they start fighting uncontrollably, you can stop oscar fish fight by keeping them alone or in a species tank.

Oscar Fish is not compatible with these ultra-aggressive fish species that can scare the shit out of them.

Feeding your Oscar

Feeding your Oscar is essential, as they are omnivores and need a balanced and nutrition-rich diet. Oscars will eat fish, shrimp, and snails. In addition, you can feed them a mix of flake, pellets, and live food.

The amount you should feed your Oscar depends on its tank size; for example, if you have an aquarium that’s 20 gallons or less, you should only give your fish about 1/2 to 3/4 of a flake per day.

You may want to supplement with vitamins and minerals as well. If the tank is more significant than 20 gallons, then it’s recommended that you double the number of flakes given daily because Oscars grow faster in larger tanks (and massive ones).

Oscars will eat anything small enough to swallow whole—so don’t keep them with any fish that are too small!

Breeding Oscars

Getting your Oscars ready to breed can be tricky, but if you follow these steps, you’ll be able to have healthy fish that will grow up and have fry of their own.

  • First, get a male and female Oscar around the same size. You’ll want an extra-large tank (at least 55 gallons tank) if you want enough room for all of your fish, as well as space for lots of plants and caves for them to hide in.
  • Then add about 10 gallons of fresh water from another aquarium every week, so it’s always lovely and clean!
  • If you notice any dead plants or algae build-up on the bottom after cleaning out the water filter cartridges with vinegar, place one cartridge into a large bowl filled with warm tap water.
  • Add 1 cup white vinegar; soak overnight); use this opportunity to vacuum up any leftover debris before refilling it again with fresh water (this should only need to be done about once per month).
  • When changing out old filters/media cartridges, make sure they’re not blackened by dirt & dust/algae since these things reduce oxygen levels which could lead you back down into having problems again.

Setting up Oscar Fish Tank: A Fun and Rewarding Experience.

Setting up an oscar fish tank can be a fun and rewarding experience. Follow the steps below, and you’ll be on your way to having an awesome tank!

  • Talk to a pet store or fish breeder. This will give you an idea of what fish suits your situation.
  • Be patient. Choosing the right tank for your oscar fish may take some time. I believe it’s better to buy the oscar tank from an offline pet retailer than order it online, as you’ll have a clear idea of picking the right tank size for your oscar fish.
  • Be prepared to spend money (and lots). The cost of setting up an Oscar aquarium depends mainly on how much space you want for your little friend(s).
  • Now once you’ve decided to go with a 55-gallon fish tank (or an even bigger one), read this post to determine what else you want to add to your oscar fish tank.


Congratulations! You’ve now set up the perfect home for your oscar fish. Now it’s time to enjoy their company for your improved mental health and watch them grow.