Oscar – Astronotus ocellatus

Oscar – Astronotus ocellatus main image Oscar – Astronotus ocellatus image

Oscar - Astronotus Ocellatus


Natural Habitat

Oscars can originally be found to have come from the Amazon River South America and prefer shallow, calm freshwater rivers or basins. The water quality of where they are found has a neutral pH level between 6 – 8 with moderate hardness and tropical temperatures. As they are mostly bottom dwellers and feeders, they like their environment to have sandy or muddy substrates.

Maximum Size and Longevity

If well looked after Oscars can grow up to 40cm and live for ten years.

Water Quality

· Temperature: 24°C - 26°C.

· pH: 6.0—8.0

· General Hardness: 100—200 ppm.


Oscars are most compatible living with other large fish. It is interesting to note that when Oscars are juvenile they tend to be a bit more aggressive however as they age and grow their aggressiveness decreases.


 Oscars are particularly good feeders and are highly carnivorous. They thrive on a combination of live, frozen, and dry food. Be aware that Oscars will readily eat smaller fish. Oscars can become quite unwell if they are overfed or do not have the appropriate vitamins such as vitamin B & C in their diets. Overfeeding will lead to fatty degeneration of the liver. Poor diet can lead to a problem known as ‘Hole in the Head’ where patches of tissue degenerate around the head leaving large holes in the tissue.


Oscars are sexually monomorphic meaning that there are no visible physical differences between the male and female. When breeding Oscars can become quite aggressive and will fight causing injury or death. When ready to lay eggs, Oscars like to dig a nest often in a gravel substrate, eggs will hatch after 2 – 3 days.

Colours and Varieties

Breeding of Oscars has seen a wide range of colours created. Most common colour colours are tiger, red and albino. In recent times changes to the tail of Oscars is being developed with some Oscars now having long or veil tails.

General Information

Oscars are most popular at the 4-5cm stage however can quickly grow up to 25cm within a few months. Oscars are known to be easy to maintain with their primary needs being a large tank without small fish and an effective filtration system as they are very messy eaters.




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