Oscar Care + Interesting Facts (Beginners Guide To Keeping Oscars)

Oscar fish

Oscars are popular for their striking colors, long lifespan, and intelligence.

They make excellent pets for seasoned aquarists as their unusual behavior can keep you captivated for hours.

Let’s learn about these dazzling fish in more detail.

Oscar Species Overview

Oscars are freshwater fish native to the Amazon and Orinoco Rivers and tributaries.

They’re a species of the cichlid family from South America and found in Brazil, Argentina, Paraguay, Venezuela, Columbia, Peru, Uruguay, and parts of French Guiana and Suriname.

Oscars primarily inhabit the slow-moving waters with lots of submerged vegetation, rocks, foliage, and debris that provide them spots to hide from predators.

Since oscars are primarily found in the Amazon basin in areas with a strong current, they don’t get affected by the currents even in captivity.


Oscar in an aquarium

Oscar fish are also known as tiger oscars or marble oscars due to their black, brown, and orange markings.

Oscars have a long and oval-shaped body. They have large heads with big eyes and wide mouths.

Their anal and dorsal fins extend from their head to tail, forming a beautiful fan shape.

Oscars are distinguished by their large black spot with a bright orange ring around them on either side of their tail fin.

They’re dull at birth, and their dark markings are deep black.

Their color brightens, and the black markings turn grey as they grow.

Young oscars have wavy orange and white bands with small white spots on their head.

On the other hand, adult oscars have brown or black bodies with orange or red markings.

Some oscars even have green or olive bodies.

Albino varieties of the oscar fish come in different colors, including white bodies with red patterning.

Another distinctive feature is that they’re monomorphic, meaning the male and female oscars look exactly alike as there is no noticeable difference in terms of physical appearance or size.

Names of Species

The most common type of oscar fish is the tiger oscar.

But many different varieties of oscar fish are produced via selective breeding.

So you can find oscars in vivid colors and patterns.

Crossbred variety of oscar fish include:

  • Albino oscars with boldly white color and white fins,
  • Blue oscars with blue patterning,
  • Black oscars with white bands running throughout their bodies,
  • Green oscars with green and yellow coloring, and
  • Red oscars with red or black fins.


Oscars generally live up to 20 years in the wild. Male and female oscars have the same average lifespans.

In captivity, oscars have an average lifespan of 12 to 15 years.

However, just like in the wild, oscars can live up to 20 years in-home aquariums if they get a conducive environment and good care.

Average Size

Among aquarium fish, oscars stand out due to their size. A fully grown oscar reaches up to 12 inches in captivity.

Oscars grow even longer in their natural habitat.

They can grow up to 16 inches, making them one of the largest freshwater fish species.

Oscar Tank Setup

Oscar tank

The ideal tank setup for oscars is the one that closely resembles their natural habitat.

Hence, the best tank for oscars should be large enough to accommodate all the plants and other equipment they need to thrive.

Let’s understand the tank requirements of oscar fish in more detail.

Tank Size

The size of the tank is crucial while keeping bigger fish species.

Since oscars can grow up to a foot in length, they need a big tank of at least 55 gallons for a single adult fish.

If you plan to keep more than one oscar fish, then the tank needs to be bigger.

As a general thumb rule, you need to add 20 to 30 gallons of water for every additional oscar fish.

Apart from the tank size, the shape of the tank is equally vital.

The ideal tank shape is wide so that the oscars don’t bump into the tank while swimming.

A large tank also allows the creation of their natural environment, which helps oscars feel comfortable and happy.

Tank Equipment And Decorations

The natural habitat of oscars is one of the most biodiverse environments.

So it can be challenging to replicate their natural environment.

However, you can always make oscars feel comfortable by providing them with all the necessities to help them thrive.

Oscars need a freshwater tank with a soft, sandy substrate having vegetation, debris, and rocks scattered on top.

You need to avoid keeping a coarse gravel substrate as it can injure the fish.

Floating plants and robust plant species such as hornwort are excellent for the oscar fish tank.

Other live plants such as java fern and java moss can also be used to replicate the underwater greenery of their natural habitat.

Oscars have a habit of digging up plant roots and breaking the aquarium equipment.

So plants should be hardy and firmly rooted, and tank decorations should be placed firmly.

The best solution is to use plant weights or clay pots to secure the plants until the roots are well-established.

Incorporating a sump is also advisable to move the life support equipment out of the tank and away from the fish to avoid destruction.

Some of the items required in an oscar fish tank are:

  • A high-quality filtration system,
  • Heater,
  • Powerheads,
  • Robust live plants,
  • Standard LED aquarium lights. and
  • Decoration such as driftwood, rocks, bogwood, caves, etc.

Oscar Care

Healthy oscar

Oscar fish need moderate care.

A large tank with clean water, suitable and stable water parameters, a nutritious diet, and strong water flow is critical for their thriving.

Let’s now see how you can take proper care of your oscars.


Oscars are omnivores fish.

In their natural habitat, they feed on plant matter, small fish, insect larvae, live insects, snails, shrimp, crustaceans, fruits, and nuts.

You should feed oscars a well-balanced diet in captivity that provides the essential nutrients.

You can feed them cichlid or oscar pellet food, specifically designed for them.

Plant-based food such as green veggies and algae wafers are also a healthy option for oscars.

To meet their protein needs, you can feed them live or frozen food like bloodworms, brine shrimp, daphnia, tubifex worms, frozen krills, mealworms, or earthworms.

The feeding schedule varies depending on the age of the fish. Young oscars need little food compared to older ones.

Feeding also needs to be done twice a day. You should feed them only the amount that they can finish in a couple of minutes.

Water Parameters

Oscars are softwater fish. They’re sensitive to variations in the pH levels of the water.

So you need to avoid adding limestone, coral, or any other calcium carbonate-based minerals that can change the pH levels.

Water parameters need to be stable to avoid stress.

Drastic fluctuations in water parameters can negatively impact the health of oscar fish.

The ideal water parameter for oscar fish are:

Water temperature74°F to 81°F (23.3°C to 27.2°C)
pH level6 to 8
Water hardness5 to 20 dH

Tank Maintenance

Oscars are highly sensitive to water changes. So it’s crucial to maintain the water chemistry that suits them.

Oscars are also very sensitive to ammonia and nitrites. So it’s vital to cycle the tank before introducing them to the new tank.

You need to clean the tank regularly with a partial water change of 20% every 15 days.

You should also clean the decorations and substrate to avoid the accumulation of dirt and debris.

When cleaning the tank, remove any rotting organisms and debris using the siphon method.

Also, ensure that there are no sharp objects left behind.

Water needs to be tested regularly to avoid the buildup of ammonia or nitrates that can pollute the water and make the fish sick.

Common Diseases

Oscar fish aren’t immune entirely.

They’re susceptible to numerous fungal and bacterial infections if the water and tank aren’t maintained appropriately.

Some of the common oscar fish diseases are:

  • Hole in the head,
  • Columnaris (Fin Rot),
  • Ich,
  • Dropsy or Bloat, and
  • Popeye Disease.

Oscar Behavior And Temperament

Oscars belong to the cichlid family.

So they have a reputation for being aggressive, especially when the conditions are unsuitable.

Oscars can become territorial in a cramped space due to overcrowding or incompatible tankmates.

They also become aggressive if other fish invade their territory.

Oscars can attack or chase the other fish away to defend their territory.

However, when kept in a favorable environment, oscars are a delight to watch as they’re intelligent species that recognize their owners.

They’re sometimes called water dogs as they come near their owners when they see them and shake their tail fin or head, just as dogs wag their tails.

Oscars are fast swimmers that frequent the middle section of the tank.

They can occasionally swim to the tank’s bottom to scavenge for food scraps on the substrate.

Oscar Tankmates

Oscar with tankmates

Oscars are semi-aggressive fish. So you should carefully select their tankmates to ensure peaceful coexistence.

The safest option is to house a group of oscars, provided the tank is large enough to accommodate all the fish.

Oscars live in relative harmony with each other as long as each fish gets ample space to claim its territory.

Some of the compatible tankmates for oscar fish are:

However, you should avoid keeping certain fish with them.

Given below are the fish that you should avoid housing with oscars:

  • Small fish such as guppies, tetras, goldfish, cherry shrimp, snails, etc., as they’re a tasty snack for the oscars.
  • Large and highly aggressive fish such as African cichlids as they can bully the oscars.

Oscar Breeding

Breeding oscars can be challenging as they’re picky in selecting mates.

Putting a male and female oscar in a tank with suitable conditions may not necessarily result in breeding.

So you need to be patient and wait until the right time.

Oscars reach reproduction maturity when they reach 16 months of age.

They usually form a life-long pair. So it’s better to purchase oscar fish that are already a pair.

You can follow the below steps to breed oscars in captivity.

  • After forming a pair, you need to breed oscars in a separate breeding tank away from other fish. The tank should be large with conditions similar to their natural habitat during the breeding season.
  • Temperature is critical to induce spawning. It should be around 78°F to 84°F (25.6°C to 28.9°C).
  • You need to change the water every couple of days as oscars need clean water to breed.
  • Feed your oscar pair a varied diet of live and frozen food rich in protein.
  • Mating will take place once the pair gets interested.
  • The female oscars usually lay eggs 2 to 3 days after the mating ritual. They lay eggs in batches of hundreds and around 3000 eggs over a few days.
  • The oscar fry will hatch from the eggs within three days of being laid.
  • Not all eggs laid are viable. The parent oscars guard their eggs until they hatch. However, it’s not uncommon for them to eat their eggs if they’re stressed or feel unsafe.
  • You need to remove the oscar pair from the breeding tank once the fry are born to prevent them from eating their fry.
  • For the initial few days, the fry don’t need feeding as they have an egg sack that they consume. After the fourth day, you can feed the fry with infusoria and move to brine shrimp within a week.
  • Once the fry are grown, you can move them to the main tank and feed them food similar to adult oscars.

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