Oscar

1 Species Overview

The Oscar is a fairly common tropical fish: large-bodied and slow-moving. Although not fierce in temperament generally, its appetite is astonishingly large. Experienced keepers even train Oscars — some learn to recognize their owner, and a few well-trained ones will leap above the water surface to take food from a hand.

Origin: Amazon basin of South America — Guyana, Venezuela, and Brazil. Suitable temperature: 22–26°C. Water: pH 7.0–7.5. Aliases: piglet fish, tail-star fish, black-pig fish, star cichlid; family Cichlidae. Temperament: very aggressive — it may kill its own kind or eat its own fry, yet once bonded with other fish it will even protect them.

2 Morphological Characteristics

The Oscar is a very distinctive ornamental fish that, after taming, can recognize its owner. Although aggressive and prone to fighting other fish, it will protect other fish once it has lived with them a long time. Keeping Oscars is quite interesting, which is why they are so popular.

The Oscar is one of the larger tropical fish, reaching about 30 cm in captivity, with several color varieties now available. It is stocky and thick-bodied, oval in shape, deep and laterally compressed, with a fan-shaped caudal fin and a large mouth. The base color is black, yellow-brown, or dark green, with irregular orange blotches and red stripes on the sides that look like a map — hence the name. Mature fish show a large black spot with a red-yellow edge on the caudal peduncle, shaped like an eye; this acts as a protective and luring coloration that confuses prey about which end is the front. Because the body is dark, it is also called the black-pig fish. The base of the caudal fin has a fin ray black in the middle and golden-yellow at the edge, made of shorter serrated spines in front and longer rays behind; the pelvic fins are long and pointed; the caudal fin edge is rounded.

Although the Oscar’s color is plain, its shape is unusual and has unique ornamental value; its flesh is also tasty, giving it food value. Reportedly, after being hand-raised, Oscars become quite affectionate — when you approach the tank they swim over to welcome you.

3 Habitat & Living Environment

The Oscar is not demanding about water quality and is one of the larger tropical fish, reaching 30 cm in captivity, so a fairly large aquarium is essential.

Oscars are easy to keep and not hard to breed, which is why they are popular. They are not fussy about water — they do fine in weakly acidic, neutral, or alkaline water — and the suitable temperature is 22–26°C. They look clumsy but swim nimbly, hunt with agility, and are greedy eaters that prefer live animal prey; as carnivorous aggressive fish they eat tubifex worms, tadpoles, small fish, and shrimp, so they should not be mixed with other fish. At home, mind their omnivory: besides small fish, shrimp, and tadpoles, you can also offer lean meat, so their diet does not become so single-minded that they refuse anything but fish and shrimp.

Because Oscars are large, choose a sizable tank, plant some aquatic plants, and change about 1/5 of the water each week. Their color varies with age and brightness depends closely on light, so provide ample lighting. Oscars are bottom-water fish, grow fast, and are long-lived — they can live over 10 years, truly a long-lived tropical fish.

4 Feeding Guidelines

Oscars are not demanding about water, but because they are so greedy, feeding method matters — scientific feeding keeps them prettier and healthier.

Oscars eat a lot and excrete heavily, so they grow fast — about 3 cm per month. But that heavy waste badly pollutes the water, so feed in portions, a little at a time, never to 100% fullness. At home, mind their omnivory: besides small fish, shrimp, and tadpoles, you can also offer lean meat so their diet does not become so single-minded that they refuse anything but fish and shrimp.

Oscars are greedy, prefer live animal prey, and are carnivorous aggressive fish that eat tubifex worms, tadpoles, small fish, and shrimp — so they should not be mixed with other fish.