Blue Diamond Discus

A solid metallic blue with no bars or markings on the body. It became popular in the early 1990s, and it was developed from cobalt and turquoise lines.

Sources disagree about the eyes: a discus society prefers red, and one care guide says black. A settled fish should not keep dark bars, which can be a sign of stress. Discus with very similar genes are sold under different names, and one seller's name may not match another's, so judge a fish by its pattern, body colour, pepper (fine black speckling) and eye colour.

Sexes are hard to tell apart by eye. Mature males may be larger with a broader head, but the breeding tubes and spawning behaviour are more reliable.

Keep a group of at least five or six in a tall, mature tank with excellent filtration, calm flow, open feeding space and vertical cover. Quarantine all new fish.

A calm, shoaling cichlid that can become shy, bullied or underfed in too small a group.

Groups form a pecking order. Pairs separate to spawn and may need their own breeding tank.

Breeding pairs defend a vertical surface and the area around it. Outside breeding, aggression is mainly social ranking.

Use calm, warm-water tankmates that do not nip fins or take all the food. Small fish and shrimp may be eaten.

Captive-bred discus are usually kept at pH 6 to 7, and can take up to 7.5 if it stays stable. Temperature and water cleanliness must stay consistently high.

An omnivore that does well on varied pellets and frozen foods.

Feed several small meals a day, and remove uneaten food quickly in warm water.

Pairs lay on vertical surfaces. Both parents guard the eggs and produce a skin mucus that feeds the fry for about their first four weeks.