Rainbow Cichlid

Adult fish usually reach about 7 cm, though the maximum recorded length is 15 cm. Males are typically slightly larger, but sexual dimorphism is otherwise weak. The body is stocky and oval with pointed dorsal and anal fins. Colour ranges from golden to orange tones. The fins, except the pelvics which have a blue tint, are the same colour. A jagged black horizontal band runs along the body from head to tail.

These fish occur naturally in Central America, from Honduras to Costa Rica. They inhabit numerous rivers flowing into the Atlantic Ocean, as well as small lakes and swampy areas. These waters are characterised by calm conditions, sandy-silty substrates, abundant leaf litter and driftwood. The water levels and temperatures in these habitats fluctuate seasonally.

The rainbow cichlid is known for its peaceful and calm temperament. The exception is during spawning, when it becomes territorial and aggressive in defence of its brood. It can be kept singly or in groups. It is compatible with other non-aggressive fish such as tetras, danios and small catfish. In spacious aquariums with sufficient shelter, it can be kept with some Central American cichlids, such as Cichlasoma species.

A pair of rainbow cichlids needs a tank of at least 80 litres; larger groups require proportionally larger volumes. Use a fine gravel substrate, stones, and roots or driftwood for shelter. Live plants, both floating and rooted, are welcome; plant them in dense groups and leave open areas for swimming. The fish prefer weak or moderate water flow and effective filtration. Lighting should be moderate, so avoid light-demanding plant species. Perform a weekly 20% water change, regularly clean the substrate of organic waste, and remove debris from decorations and glass.

This species is undemanding in diet and readily eats dry, frozen and live food. It is important that the diet includes plant matter, such as spirulina flakes or pieces of nori.

Because of their spawning behaviour, breeding is best done in a separate tank. Not all fish of opposite sex will pair for reproduction. Cichlids typically choose their own mate as they mature, and the pair remains stable long-term. Buying a new male or female and simply adding it to the tank does not guarantee pairing. Spawning is stimulated by maintaining specific water parameters: pH 7.0, water dGH 5–10, temperature around 28°C, and regular feeding of live food. When fish are ready to spawn, they darken in colour. The female may lay over 1,000 eggs at once on a stone or other ornament. The incubation period is about 3 days. Parents actively guard the eggs and fry for several weeks until they reach a certain size.

Most diseases in these fish result from unsuitable conditions that weaken immunity and increase vulnerability. At the first sign of illness or unusual behaviour, check the main water parameters and the concentration of nitrogenous compounds. Improving conditions usually helps, and the fish's immune system can often overcome the problem. In severe cases, medication may be needed.

When selecting a healthy fish, look for activity and clean skin: there should be no white patches, sores or damaged fins. A healthy fish is curious, does not hide constantly in corners, and reacts actively to movement at the glass. Avoid specimens with sunken bellies or signs of starvation, as these may indicate internal parasites or chronic stress. If there are dead fish in the shop tank or the water looks cloudy, do not buy from that tank due to high infection risk.