oscar fish

Oscar Fish: Their Origin, Types, Growth Rate, Lifespan, Care and Breeding

Oscar fish is one of the most popular tropical freshwater fish. This freshwater fish is renowned for its charming beauty and aggressive nature. Moreover, they are brilliant and entertaining as well.

These temperamental creatures have always caught the attention of fish hobbyists not just because of how magnificently beautiful they are but also their erratic personality.

They are hard to keep as a pet, but once they get along, you will love them.

 Now let’s learn about this amazing fish together. Shall we?

Oscar Fish Guide

Oscar fish also bionomically named “Astronotus ocellatus”. They are known around the world by another common name, “Tiger Oscar fish”. Some fish experts also refer to them as Marble Cichlid or Velvet Cichlid .


Oscars are the inhabitant of the “Great Amazon River”. Moreover, they are also seen in the basins of Brazil and around South America. They love to stay warm and cannot tolerate a cold environment. So, they locally inhabit warm areas of the river while being submerged in shady branches.

Scientific nameAstronotus ocellatus
specieA. ocellatus

Oscar fish also bionomically named Astronotus ocellatus. They are known around the world by another common name Tiger Oscar fish. Some fish experts also refer to them as Marble Cichlids or Velvet Cichlids.


Oscars were first referred to as “Lobotes ocellatus”, but, later it was found that they closely resemble Astronotus species. They were found in the very slow-moving waters of the White-Water River. Some species were also reported from Florida and China.

Some people also claimed to have seen this fish in Northern Australia. For their beauty and ultimate aggressive behaviour, they are named Oscar fish. 

These Cichlids cannot thrive in low-temperature areas, so they can hardly be seen in areas where the temperature is less than 12-13 degrees centigrade.


When it comes to appearance, this fish is breathtakingly beautiful. Their mesmerizing beauty can behold anyone. Every fish hobbyist love to have this magnificent creature in their collection. The wild species have more vibrant colours with orange, white circular strips across their body.

Young fish have dull pigmentation as compared to adults. Adult form has spots upon their head. Most Oscar fish range from 18-20 inches in length and almost more than 1.5 kg in weight. Oscar fish can get extremely large in size within a very little time. Some species of Oscar are capable of changing their colouration to some extent.

Albino Oscar Fish

They lack usual black pigments, have large and small orange-red spot upon their body. Albino Oscar is also called Red-eyed albino fish, referring to their red-coloured eyes. Many local breeders developed many new varieties with unique colours. The most famous crossbreed is all black and albino Oscar fish.


This world is full of different types of this wondrous creature. Oscars have seemingly endless varieties based on their exciting colours.

Depending upon different colours, there are many types of Oscar fish as follows.

  • Tiger Oscar
  • Red Oscar
  • Green Oscar
  • White or albino Oscar
  • Blue Oscar
  • Florida Oscar
  • Lemon Oscar

Based on the shape of its tail Oscar has another very unique type called veil tail Oscar. Moreover, fat Oscar and bumblebee Oscar are famous types.

1-Bumblebee Oscar

2-veil tail Oscar

Tiger Oscar

The most popular and highly demanded type of oscar fish is the tiger oscar. They are generally chocolate brown in colouration with bright orange firey stripes all over their body. On their dorsal fin, you can see some eyespots that are orange-red in colour.

Tiger Oscars are quite an aggressive species. Their favourite living space is a large tank with a sand base and plenty of live plants and rocks. Initially, they are territorial and can fight their tank mates for space, but they get along with time.

Life Span

Oscar fish is quite hardy, so they live longer than most fishes. Also, because of their aggressive and territorial behaviour, they can easily survive the predators. Oscar can typically live for almost 10-12 years if they do not get sick.

Oscar fish can catch a lot of diseases easily, resulting in their early death. Despite that, some of them can live up to 18-20 years.

Oscar Fish Aquarium

The fish tank should be designed according to the needs of the inhabitant fish. Keeping an Oscar fish in the home aquarium is much easy and entertaining as well. They prove to be good pets. In addition to just being beautiful and attractive, they are intelligent and interesting too.

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In my opinion petting, an Oscar is a lifetime experience, and you guys should also give it a try.

Like any other pet, Oscars also have certain needs. Furthermore, there are certain care tips that you should always remember while keeping an Oscar fish at home.

Tank Size and Growth Rate

Oscars are astonishingly great at growth. They can grow at a rate of 1 inch per months. That is an amazing thing on their part, but it can get a little burdensome for the fish keepers. So, while buying an aquarium for Oscar fish, you should keep their size and growth in mind.

A 55-gallon tank can work initially, but you have to change it after a couple of weeks. So, keeping that in mind, you should prefer a larger tank of almost 75-gallon tank. Larger species require more space, so a tank having a size of almost 125-150 gallons will be great.

Water Parameters

Oscar fish originally came from slow-moving, low pH, warm water areas, so you should prefer to provide the same conditions in the aquarium.

The optimum conditions for Oscars are the following.

  • Temperature: 77-80-degree Fahrenheit
  • pH: 6.0-7.5
  • Sensitivity toward ammonia, nitrate and nitrite.

Oscars are more sensitive to rapidly changing water parameters. To provide the best-growing atmosphere to your fish, focus on maintaining the same water condition instead of focusing on ideal conditions.

They have immense sensitivity toward ammonia, nitrate and other nitrogenous compounds. Nitrate concentration should be kept at less than 40 ppm.

Therefore, keeping the tank clean should be your priority. Try to change almost 25% of the water every week. Avoid using any harmful chemicals or soaps for cleaning.

Siphon is perfect for gravel-based tanks. While setting up the aquarium, start with a layer of a soft substrate. Sand will be the best choice because these fish are quite active to dig around.

Using a water filter with a power of 80 watts per hour is good for your fish as Oscar’s desire slowly moving water so that a water pump should be avoided. A high-power water filter can substitute for the water pump as well.

Decorations and Plants

Decorating your aquarium is a fun activity. This species can dig around the tank so that live plants won’t be a good option. Floating plants are best to use. Duckweed and hornwort are good to go.

Making a couple of caves in the tank is also an entertaining activity for your fish. Furthermore, such decorations can satisfy their territorial nature. Just remember to fix these decorations firmly.

Cycling Your Tank

Oscars are extremely sensitive to nitrates and nitrite so cycling your tank before adding the fish is a basic necessity. Start cycling the tank at least two weeks before the fish. This will clear the water and make it less vulnerable for the fish.

In addition to this use of biofilters and nitrifying bacteria is also needed.

Oscar Fish Food

Oscar fish is omnivores in nature, so whether it’s plant roots or insects, it is totally acceptable to them. To maintain their pigments, they prefer live food, including brine shrimp, small feeder fish and bloodworms.

Small fish, larvae, and plant debris is their usual food in their natural habitat. The Oscars greatly appreciate anything smaller than their mouth. A large part of their diet constitutes insects, crustaceans and snails.

While in captivity, these fish can eat anything, including flakes, pellets and frozen or dried worms. The best choice is providing your fish with live food. This will ensure the encouragement of their natural chasing and hunting instincts.

Some fish experts also suggest giving a handmade meal for your fish containing vegetables and eggs or meat for protein content. Oscars have impressive colours, so to maintain their pigments, they should get an appropriate amount of protein and vitamins in the diet.

Oscars should be fed a couple of times a day to maintain their enormous size, but overfeeding should be avoided.

Tank Mates For Oscar Fish

Regarding their aggressive and competitive nature, many of you must be worried about their tank mates. So here is a complete list of fish that can get along well with Oscars.

Suitable Tank Mates

  • Green terrors.
  • Jack Dempsey
  • Jaguar cichlids
  • Arowanas
  • Convict cichlids
  • Sailfin plecos
  • Silver dollars
  • Severum cichlids

Fish that should be avoided are the following.

  • Other Oscars
  • Small fish like goldfish
  • Barbs
  • Small catfish
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Other factors that can initiate aggressiveness between Oscars and its companions is small space, lack of food and irritating nature of other small fish. So, avoid overfilling the tank. At least a room of 55 gallons per Oscar fish is a basic requirement. The lesser space will lead to tension in the aquarium.

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Male and Female Oscar Fish

Distinguishing between the two genders is a bit tough as there is technically no visible differences between them. Their shape, colours and size are almost the same. Just that the females are more vibrant in colours. Moreover, males have a greater growth rate as compared to females.

Such minor differences are hardly helpful. Their gender differentiation becomes quite easy when the Oscars reach maturity. Therefore, juvenile Oscars are almost impossible to separate on a gender basis.

Oscars Venting

The process of differentiating the oscar fish based on their genitals is called “Oscars Venting”. In this process, we notice the shape, size and colour of their genitals. It is done by putting the fish in a net and keeping the net in the water. Meanwhile, turn the fish upside down carefully and observe their genitals.

How to Breed Oscar Fish

Breeding Oscars is the hardest thing to do as they require enormous space, abundant food and ideal conditions. Moreover, Oscar really minds intrusion by other tank mates and by the keeper as well. So, when introducing them to breeding, try a separate breeding tank for them.
Several basic steps lead to the successful breeding process.

  1. Conditioning the Oscar Fish

    First of all, prepare your fish for the reproduction process. It constitutes almost 2 weeks. Start by separating the pair after every 2-3 days and feeding them separately. Females should be fed more to achieve better quality eggs.
    This conditioning process helps in making them healthy and strengthen them enough for the breeding process. After one day of separation, put them in one tank, and they will be attracted toward each other and try to reproduce.

  2. Spawning Process in Oscar Fish

    Secondly, increase the temperature of the breeding tank to at least 80-85 degrees Fahrenheit. The higher temperature is considered helpful in triggering the breeding process. Next, the pair will require a flat surface or smooth slab for laying eggs. When they are ready for mating, their breeding tubes will drop, intensifying their colours.

  3. Taking Care of The Eggs

    Both the parents participate in taking care of their eggs. Oscars generally lay almost 1000-3000 eggs at a time. They protect the eggs from any predator. They can even get scared of you, so avoid checking them regularly.
    Any danger or attack from a predator can evoke their aggressiveness, and they can attack back any time.

  4. Building the Tank for Eggs

    After 4-5 days, the male Oscar usually build a small hole in the substrate and move their eggs there. Within almost 10 days, the fry can become free swimming and motile. Now is the time for the breeders to separate the young ones and shift them into another tank.
    Feed the offsprings with bloodworms or shrimps. Different frys have different rate of growth. Smaller ones should be protected from larger frys.

Oscar Fish Care

There is a wide range of diseases that the Oscars are prone to. Diagnosing the disease and finding its cure is necessary for the survival of your fish.

Some of the diseases might not be fatal, but they can still make your fish weakened.

  • Hole in the head disease
  • Ich disease (white spot disease)
  • Tail rot
  • Fin rot
  • Popeye disease
  • Bloat or dropsy
Hole in the head disease

Although Oscars are susceptible to many diseases if not taken care of, but hole in the head disease is quite common. Among fish keepers, this disease is also known as head and lateral line erosion (HLLE).

Hole in the head disease is characterized by ulceration and skin deterioration around the head, particularly on the lateral side and dorsal fins. Fish can experience pain and irritation. Aquarists have found that the use of activated carbon is a contributing factor in the spread of disease.

How to protect Oscars from diseases?

Generally, to avoid any sickness or disease, you should keep in mind the following health care tips.

  • Regularly checking the aquarium water parameters and maintaining low concentrations of ammonia and nitrates.
  • Change the filter sponge and the rest of the cleaning material.
  • Don’t overcrowd your aquarium.
  • Installing a thermometer is a good health measure to maintain temperature.
  • Always keep the new fish in a separate aquarium for a minimum of two weeks to check its health.
  • Treat your sick fish in a separate tank as soon as possible as it may affect other fish in the aquarium.
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Oscars are infamous for their dominating personality. Due to their rapidly increasing size, they usually tend to suppress the other fish around them. Just like any other large fish, Oscars also tend to eat their smaller companions. Moreover, they try to win the available space by terrorizing their tank mates.

This typical temperament of Oscar scares the beginner fish keepers, and they start getting second thoughts about having it. Although petting an Oscar is not that big of a deal as they get along well with time.

Giving them appropriate space and enough food to eat is an absolute solution to their aggressiveness. Oscars usually colonize the middle part of the tank most of the time, but sometimes they like to dig around for fun. So, try to fix your aquarium well before putting the Oscar fish in.

Oscar Fish Price

Depending upon their size and type, Oscars can vary in their price tag. Still, they are not quite the cheapest. Oscar fish can range from as low as $8 to almost 100$ in price.

Thus, Oscars are not just difficult to care for. They are even difficult to purchase as they can really give a spin to your pocket. Moreover, their food expenses and tank expenses can altogether get a little out of hand thing. Still, fish hobbyist never misses the opportunity of having this remarkable fish.

Interesting Facts about Oscar Fish

Oscars are full of adventures. They are interesting and intelligent creatures. Here is a list of some interesting facts regarding Oscar fish. Let’s take a look.

  • They are quite brainy and are quick learners. Oscars are one of those fish that can be trained to perform tricks.
  • Oscars are friendly with their owners so that you can even enjoy hand-feeding them.
  • They are astonishingly bright at growth. They can grow up to 18-22 remarkable inches. Thus tank size should be enormous to allow appropriate growth.
  • Oscars are also blessed with the ability to camouflage in the dark to hide from predators.
  • They have surprisingly sharp teeth and jaws. In addition to that, Oscars also contain a set of teeth at the back of their throat.
  • Oscars require vitamin C as a major constituent of their diet.
  • Lastly, they can pretend dead to hide from predators.

Frequently Asked Questions(FAQs)

Although we have tried to provide every tiny little detail about Oscars, if we couldn’t mention any important point, we have answered some of your queries about this mesmerizing fish.

1-How many Oscar fish can stay together?

Oscars usually enjoy each others company, but due to their hostile and territorial nature, they can fight for dominance. Thus if you wish to keep Oscars together, you should keep at least 4-5 of them.
Keeping Oscars together requires lots of space and constant care. Initially, they fight a lot and may injure each other at times, but they get along well after some time.

2-How do you keep Oscar fish?

Oscar fish is a hardy creature, and its survival rate is amazing. Oscar tank should have clean, warm water and plenty of space. They enjoy digging; thus, a sand-based aquarium with floating type of plants and rocks is highly appreciated. The minimum tank size should be 55-75 gallons.
Being omnivorous, they are good with anything when it comes to food. Plants, small feeder fish, crustaceans, insects, worms, brine shrimp, fish pellets and snails.

3-How can you tell a female Oscar from a male Oscar?

Differentiating the two sexes is usually difficult until they are mature. Females are usually brighter and more pigmented. But the main difference lies in their genitals.
By the process of Oscar venting, we can see that females have two holes, and one is bigger than the other. This bigger hole is actually their egg tube. In contrast, male Oscars have the holes of same size and shape.


Altogether Oscars are brilliant creatures, and keeping them as your pet can prove to be a lifetime experience. Here ends our journey with this beautiful part of nature. I hope you got all you needed.

Looking forward to your great reviews.

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