Discus

1 Species Overview

The Discus is a very famous ornamental fish. Its unusual disc shape and rich, shifting colors and patterns make it a favorite, earning it the nickname ‘king of tropical aquarium fish.’ Prices keep rising, and new hybrids are still being bred.

It is a cichlid (order Perciformes, family Cichlidae, genus Symphysodon), with the scientific name Symphysodon discus. In Chinese it is called the ‘seven-colored fairy fish,’ and its nicknames include the iron disc.

2 Morphological Characteristics

Because the Discus is so beautiful and unusual, it is called the king of tropical aquarium fish. Its body colors range through red, green, blue-green, and blue.

By pattern, if the main vertical stripes cover more than 75% of the body it is grouped as a ‘turquoise’ type. By shape there are wide-fin forms (still disc-shaped), high-body forms, and high-body wide-fin forms. Names vary by region — red turquoise, blue turquoise, cobalt blue, turquoise, solid blue, glowing disc, big disc, and so on.

A common misunderstanding: the name ‘pigeon red’ discus refers not to red on the body but to the eye color — like the prized pigeon-blood ruby. A good pigeon red has blood-red eyes.

3 Habitat & Living Environment

As prices rise, raising healthy, pretty discus matters more, and a suitable environment is the first step.

Use a wide tank. Discus need a large, calm body of water; a bigger tank keeps the water more stable. Keep them in a group — alone they get lonely and fight, and a group is less likely to fall ill. Eager competition at feeding is a sign of health; too few fish lose that drive and get sick, just as an only child is more delicate than many siblings. With more fish you need a stronger filter or the water clouds. A 1.2 m tank with about 20 discus is spectacular; fewer than 10 looks empty. A bare tank can hold more.

For the scape, use a bare or half-bare tank. You can add a few high-quality fake plants (real plants and sand are harder to clean). More plants means fewer fish if the view is the point; more fish means fewer plants. You cannot maximize both.

4 Feeding Guidelines

Besides the environment and water, scientific feeding is key. Follow the ‘four fixed’ rule: fixed time, fixed amount, fixed quality, fixed place.

Time: morning feeding beats evening, and once a day is enough for a pet (not a business). Feeding at the same time daily makes the fish eat eagerly; a little hunger means more swimming, which is exercise — in nature fish are often hungry yet thrive. Amount: fish stop when full. Start with a little, add until some fish start hesitating (that is full), and keep to that amount. If fish fail to finish in the normal time, some or all are sick — stop feeding and observe or treat.

Quality: bloodworms must be disinfected — rinse, soak 10–15 minutes, then soak in light-purple potassium permanganate 10–15 minutes, rinse, drain, wrap in a damp towel, and store in the fridge for 7–10 days. Use only lively worms; discard any that are sticky or turn white or black. Place: feed at the same spot at the same time to build a conditioned reflex — at feeding time the fish gather there, which is deeply satisfying to watch.