Oscar Fish: Types, Feeding habits, habitat, care, and more

Meet the strinking Oscar fish, which belong to the Cichlidae family of fish. In certain locations in South America they are consumed as food and in other countries such as Australia, USA and China are used as aquarium fish. Learn more about them below.

The Oscars Fish’ Taxonomy

The Oscar Fish were originally defined in 1831 by a zoologist named Louis Agassiz, who designated them as Lobotes ocellatus and believed that they were marine fish. Later they were placed inside the Astronotus genus, and its taxonomic classification was as follows:

    • Phylum Chordata, belonging to the Actinopterygii Class, members of the order of the Perciforms.
    • They are also part of the Cichlidae family and as indicated today belong to the Astronotus genus.

The Oscar Fish’ Main Characteristics.

Oscar Fish are large, brightly colored South American cichlids with a strong temperament and very lively. These magnificent fish develop nimbly up to a size of a little less than 33 cm maximum and are specialists in attracting anyone’s attention .

They have an oval and large body, thick lips and as previously indicated reach up to 33 cm long in their natural habitat, although they are generally a little smaller in captivity.

Their teeth are located in the back of the mouth, and are strong enough to bite a person vigorously. They also have pharyngeal teeth in the throat and their jaw teeth are very small, being only used to grip while the teeth of the throat process and manipulate prey.

Oscar fish that are taken from their natural habitat usually have a dark hue with orange shades next to the gill area. Moreover a black cloud surrounded by orange crowns the caudal fin.

Juvenile specimens show white and orange wavy bands or stripes, as well as spots on their heads. It’s  known that both captive-bred specimens and those in nature quickly change their coloration when they become territorial, combative or when they experience large amounts of stress. We invite you to read our article the anatomy of fish to learn lore about such a topic

How long Do Oscar Fish Live?

Oscar fish have a very long life, so they’ll probably accompany you for about 10 to 20 years, all depending on the care you give them.

How much does an Oscar fish grow?

Length: 45 cm (adult)

Weight: 1.8kg (adult)

They are very large and very strong fish

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Main Species Of Oscar Fish

There are different types of Oscar fish, which are very popular and widely available. It should be noted that several species of striking colors have been developed in captivity, and are equally popular and also available.

Let us know more about these varieties below.

Tiger Oscar Fish

This is the most common variety of oscar fish, and has the main anatomical characteristics of Oscar fish in general.

Red Oscar Cichlid,oscar fish: albino oscar fish

This variety was originally developed more than 40 years ago, and it’s a very beautiful specimen, which has a strong red hue and has all the Oscar fish’ common characteristics.

Black Oscar Fish

Oscar fish of this variety lack any other color in their body than black. Both in the eyes, the fins, the tail, the whole fish has a completely black hue, and all their physical characteristics correspond to the common ones of the species. Then, there are other derived varieties such as silver black Oscar fish.

Albino Oscar Fish

This variety is not totally albino since most of the individuals have red spots; and they have the Oscar fish general traits The oscar tiger is the most common variety of oscar fish, and has the main anatomical characteristics of Oscar fish in general.

Other types of Oscar fish

You can find in the oscar fish family, types that are unique and therefore quite rare. One of those rarest Oscar species is the «lemon oscar fish». It is also worth mentioning the dwarf Oscar fish which are poorly developed, and extremely rare Oscar fish

It also worth mentioning the short-bodied specimens, which are selectively bred to have a shorter and more compact body. There are also varieties in the Astronotus ocellatus that have been dyed or artificially illuminated to make them more attractive, but their purchase is not suggested, since such a fact causes them problems, an example of this is being the blue oscar, the bright yellow oscar, among others.

    • Blue Oscar fish
    • Gold Oscar Fish
    • Leopard Oscar fish
    • Orange Oscar Fish

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Where Do Oscar Fish Live?

The Oscar fish live in South America, mainly in Peru, Ecuador, Colombia, Brazil and French Guiana, being common in the amazon basin, the Paraná, the Paraguay River and the Negro River.

This species is not included in the IUCN Red List. The Oscar species has been introduced in the countries of China, Australia and in the city of Florida in the USA as a byproduct of the aquarium trade.

The expansion of the species in many non-native areas has not been easy as they do not tolerate cold temperature waters. In some places in South America they are used as food.

Members of this species live in the slow waters of rivers, canals and ponds with muddy or sandy bottoms, feeding on small fish, rio crabs, worms and insect larvae.

Taking Care of Oscar Fish

Like all tropical fish, Oscar fish require clean, fresh water in their aquariums, adequate food and a good quality filtration system. They also have some additional requirements due to their large size and strength.

How to choose the aquarium for proper care for Oscar fish

Oscar fish are among the largest freshwater fish, and it is not uncommon for them to grow up to 12 inches long. Due to this fact they will need an aquarium that has plenty of space for them to swim freely.

Here are some useful tips:

    • Keep only one or two Oscar fish in a large 125 gallon If this sounds excessive, keep in mind that these large fish need space to move.
    • The narrower spaces can also lead to overcrowded and unhealthy conditions, which in turn can lead to diseases. Be cautious and choose the largest aquarium size you can afford.
    • Be sure to place your aquarium on a sturdy stand or table and in a place where you can enjoy watching your fish.
    • Make sure the aquarium and table are completely level. An unequal aquarium exerts additional pressure on the side panel seals, which can cause leakage.
    • Add a good quality filtration system
    • A high quality carbon filtration system is absolutely essential for all domestic aquariums, but it is especially for Oscar fish due to the amount of waste they generate.

The function of a filter is:

    • Remove solid waste, such as food particles from water.
    • It controls chemicals and biological agents, as well as reduces ammonia.
    • Oxygenate the water
    • Fish routinely create ammonia during breathing and excretion. Unless measures are taken to remove ammonia from water, it can accumulate rapidly and kill fish.

So, make sure that:

    • Buy the best quality filtration system you can afford.
    • Follow the instructions recommended by the manufacturer for care, maintenance and cleaning.
    • Keeps your filter running at all times.
    • Remove and replace approximately 10 percent of the aquarium water weekly.
    • Aquarium lights and caps are a must for an Oscar fish aquarium
    • Oscar fish can jump, and they are known to jump to certain death from an aquarium without a lid.

Prevent the Oscars from jumping

One trick to prevent Oscar fish from jumping out of the aquarium is to keep the bottom of the aquarium lid clean . In nature, insects and the remains of plants that land in the water create a wave that attracts fish to the area.

It’s like a dinner bell ringing for them. In captivity, the moisture that drips from the bottom of the aquarium lid or the pieces of fish food attached to the hatch can trick an Oscar fish into thinking that a meal has arrived. By keeping the aquarium lid clean and secured, you can keep your fish where you want them and where they should be: in the aquarium!

Add gravel, plants and accessories

One of the oscar fish’ most fascinating aspects is based on their habit of getting tangled among the aquarium accessories. They can lift plants and even move rocks across the aquarium floor. Oscar fish are a bit messy, so don’t be surprised if they dig in the gravel or mess up the plants a bit by changing the decoration.

Since this behavior can be expensive, especially when starting live plants, consider adding artificial plants to the aquarium. Your Oscar fish won’t mind.

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Common Diseases of Oscar fish

Oscar fish are commonly affected by five general diseases such as the hole in the head (HITH), eye disease, fin and tail rot and itch. Overcrow ding and poor water quality causes these diseases.Keep in mind that hole in the head mainly affects the head and face, causing caries and pits in the head and face. It is due to a nutritional deficiency of: vitamin D, vitamin C and elements such as calcium or phosphorus, as well as partial water changes or excessive filtration of chemicals with activated oxygen as a chemical medium.

You have to check them periodically and diligently to detect injury. While growing this fish, you have to have complete information about a variety of infections such as parasitic infections, fungal infections and bacterial infections. It is also recommended that you update your knowledge about common diseases

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The Oscar Fish’ Reproductive Pattern

One of the very frequent questions asked by aquarists who are starting and yearning to reproduce Oscar fish is, how to reproduce them? There is nothing more exciting than watching a couple of Oscar fish go through the breeding ritual and then dedicate themselves to laying eggs. If eggs hatch, there is a possibility that you have several hundred babies.

However, deliberately starting the breeding of Oscar fish is something that must be carefully considered. Before you even start trying to breed Oscars, you should already have plans about what will happen to all the Oscar fish you will have. Oscar fish reproduce in the rainy season in their natural environment.

The conditions in the aquarium will probably remain the same throughout the year. Your Oscar fish will not know when it is time to reproduce and it is not uncommon for a female Oscar fish to produce eggs shortly after a major water change.

Basically, the Oscar fish has been tricked into believing that it is raining and, therefore, is the time of the year when it should be breeding. So, this is the technique to deceive them and make them think that it is the rainy season and the time to reproduce.

Simulating heavy rains in your aquarium is not that difficult. Extremely heavy rains will cool the water temperature slightly, so the water temperature will drop by approximately 2 ° C.

There are several ways to simulate rain in the water. The easiest way is to use a spray bar that when placed lightly on the water will simulate the sound of the rain that falls on the water. Although many cartridge filters come with spray bars, it might be better to modify your own sprayer with a water pump.

This way you can turn it on several times a day to simulate rain storms. Alternatively, use a watering and spend 5 or 10 minutes spraying the surface of the water a few times a day.

During the simulation period of the rainy season, feed your Oscar with insects, shrimp and blood worms. A cheap way to get the perfect insect is to incubate worms in the flour.

Signs of possible reproduction

Before Oscar fish start laying eggs, you will begin to see a very strange behavior. The female Oscar fish will want to test the male strength of the Oscar and does so by playing a kind of tug of war with him. This procedure is called «jaw blockage» and, as the name implies, the Oscars grab each other’s mouth and literally try to drag each other around the aquarium.

In addition to jaw blockage, you can also see the Oscars chasing each other sporadically, often trying to pinch themselves in the back. Jaw blockage and chase will lead Oscars to look for an area in the aquarium to lay eggs.

If you have a flat rock in the aquarium, you are likely to choose this area. Then they will begin to rub the rock with their lower lip so that it looks good and clean, so that the eggs stick together properly.

Male and Female Oscar fish

Before you can raise Oscars you need a male and a female. Unlike many other tropical fish where there is a distinctive difference between the male and the female, there is really no way to tell the difference between the male and female Oscar just by looking at them. Oscar fish are what we call «monomorphic», which means that the male and female look exactly the same (there is no sexual dimorphism)

How to differentiate a male Oscar fish from a female?

Actually, there are only two known ways to successfully differentiate a male and female oscar fish. The first involves a process called «ventilation.» You can examine their genitals and by comparing the shape and size of the opening you will determine the sex. The second and absolute 100% guaranteed way to sex an Oscar fish is when you see the female laying eggs and then the male fertilizing them. If you are lucky enough to witness Oscar fish laying eggs, you can take a look at the bottom of both fish.

Next, you will see the difference between female and male genitalia. The female genital papilla is what most of us refer to as an egg tube. It is quite wide at the end and whitish in color and stands out quite far.

When she is not laying eggs, she retracts completely. The male’s genital papilla is very different from the female’s since it only has a small spike of which it is with which it deposits the sperm.

Getting females and males Oscar fish

This is really a task that is easier said than done. In the world of cyclid fish, the female will usually choose a mate to reproduce.

Therefore, it is not just a case of buying two Oscars and waiting for them to reproduce. You may be lucky and end up with a pair of breeding fish; however, most likely you have bought two females, two males or an Oscar pair that are not interested in reproducing each other.

To increase the chances of finding a breeding pair, you will need to get several Oscars and keep them together in the same aquarium for a few months. What you expect to happen is that two of the Oscars finally separate and form a couple.

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How to raise Oscar fish?

Eggs that have been successfully fertilized will change from white to roasted brown after a few hours. The eggs will take about three days to incubate. At first, you will see that the eggs are slightly shaken when the fry begin to emerge from the shell.

Once the fry hatch completely, they will have a yolk sac hanging under them; this will feed them for about four days. Once the yolk sac has been used up, it must be fed. If your intentions are to keep oscar fish’ offspring, then you will have to take it away from the parents and put it in their own aquarium.

You are not removing the fry for protection; you will have to place them in the aquarium that has the best water conditions. Also, in order to feed them and help them grow properly, they must be completely alone without any interference from other fish in the aquarium.

Feeding the Oscar fish’ fry

Feeding the fry is not as simple as any other fish. Oscar fish fry have small mouths and it is doubtful that you have any suitable food on hand. However, there is a wide variety of baby food to choose from today, so your fish shop should have something suitable for you to use. Alternatively, take a look at eBay; you can get almost anything you want there.


Shrimp in brine are by far the best food to feed your Oscar fish fry. People have been using brine shrimp as food for fish pups for many years.

Brine shrimp are packed with all the nutrients and proteins that their Oscar fish pups need to become healthy adult fish. Shrimp in brine also activate the hunting instinct.

Brine shrimp are very easy to grow. You can buy eggs online and store them for many years in a cool and dry place. Brine shrimp eggs can be incubated in a brine shrimp farm and will usually be ready to feed their fry within 24 to 48 hours. It is quite easy to make your own brine shrimp farm, alternatively, you can buy them online for very little money.

Oscar Fish and Other Fish Species

This is not the fish for community aquariums (whatever the seller says). While the fish is young, it behaves quite well with other aquarium mates, but when it reaches 10-12 cm (4-5 inches) long and becomes reproductive, the fish also becomes aggressive and it is better to keep a mate in an aquarium since then or maybe several fish together if the capacity of the aquarium allows it.

The compatibility of oscar fish can be only with large or especially prickly fish: the jaguar cyclid fish, green terror, Jack Dempsey cichlids and other cichlids, large armored and common pleco. All fish, except these, will be eaten or at least bitten by oscar fish.

The Oscar Fish’ Behavior

The oscar species is considered the smartest available for collectors. They have and impeccable memory and are one of the few aquarium pets that can be trained to do tricks and distinguish individually their caregiver.

Unfortunately, Oscar fish are not community species, except that which can be kept with other large fish in a very large tank.

Before buying this fish it is important to realize that they grow very large as well as very fast.

Oscar fish are often acquired very small, but in less than a year they can become very large, at this point they will be the size of a small plate of food.

This variety of cyclid is very dirty and constantly defecate the food digested around the aquarium. This is partly due to its carnivorous nature and huge appetite as mentioned above. To avoid poor water quality, oscar fish require more thorough maintenance than other fish.

It’s important to have community members together from an early age. The presentation of a new oscar fish to the aquarium can promote territorial disputes that may never be resolved.

How to Distinguish an Aggressive Fish?

It’s very easy to know if an Oscar fish has signs of aggression. Usually an aggressive fish opens its mouth continuously very large and will show its guts, this makes the fish’s head look much larger than it actually is.

Oscars sometimes when you clean your tank become aggressive,But it is very rare for oscar fish to harm their owners, they have rather rough mouths that can inflict superficial wounds on rare occasions. If you have young children, it is advisable to prevent the fingers of the little ones from entering the tank.

Let’s have a final look of them


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