Neon Rainbowfish

Adults reach about 8 cm in length. Their body has a bluish hue with a characteristic neon effect. This neon glow becomes noticeable only under diffuse lighting, for example in tanks with floating plants. The fins and tail are red. Sexual dimorphism is weak. Males are usually slightly larger than females and have more intense red coloration.

This fish comes from New Guinea, specifically the Indonesian part. It inhabits the Mamberamo River basin, where it is found in the main channel, tributaries, and surrounding tropical swamps. It prefers areas with abundant aquatic vegetation, often living near submerged trees, shrubs and driftwood.

The Neon Rainbowfish is peaceful and very active. It is compatible with other fish of similar size and temperament. However, its activity may disturb slower tank mates. It should be kept in a school of at least 6–8 individuals of both sexes. Males show brighter colours when they have rivals, using this to attract females.

For a school of 6–8 fish, the tank should be at least 60 litres. Use rooted and floating plants in groups to leave open swimming space. This fish does not do well with intense lighting or strong water flow, so choose equipment accordingly. Water quality is key. An effective filter and regular partial water changes will provide suitable conditions.

The Neon Rainbowfish is not fussy about food. It readily accepts most common foods: dry, frozen, or live. To maintain bright colours, vary the diet: alternate flakes and granules with bloodworms or brine shrimp. This variety helps them show their best colours.

You can breed these fish in a community tank or a separate breeding tank. To trigger spawning, maintain water temperature at 26–28°C, slightly alkaline pH of 7.5, and moderate hardness. The tank should have dense plantings of fine-leaved plants or artificial equivalents as spawning sites. Spawning lasts about 2 weeks. During this time the female lays dozens of eggs daily, which the male fertilizes. Rainbowfish show no parental care, so after spawning they ignore the fry. In a community tank, move the eggs to a separate container with the same water parameters; otherwise they will be eaten. If a separate breeding tank is not available, use dense floating plants as shelter for the fry. Eggs incubate in about 7–12 days. Newly hatched fry need microscopic food such as infusoria. After a week, add brine shrimp nauplii or specialized fry powder. Feeding fry in a community tank is harder than in a separate breeding tank.

Health problems in these fish usually result from injury or poor conditions that weaken immunity and trigger disease. If you notice symptoms, first check the water parameters for excess values or dangerous concentrations of toxins (nitrite, nitrate, ammonia, etc.). Once you have corrected all deviations, begin treatment.

When buying, choose active fish that school together and show interest in their surroundings. Healthy fish have clean fins without erosion, intact scales and clear, unclouded eyes. Avoid specimens with sunken bellies, signs of emaciation, or unnatural behaviour such as lethargic swimming at the surface or lying alone on the bottom. Look for spots, coating or rash that may indicate parasitic or bacterial infection. Buy from reputable suppliers that maintain quarantine standards, as this species is sensitive to sudden changes in conditions and stress during transport.