Axelrod's Rainbowfish

Adult males reach about 10 cm, while females stay slightly smaller at around 8 cm. Body colour varies: the upper portion may be bluish-grey or greenish-brown, while the lower body is typically lighter with a silvery tone. Along the lateral line, 6–10 dark spots are visible; these merge into a distinct black stripe from mid-caudal peduncle onwards. The lower half of the body shows 6–10 faint dark vertical bars. The upper body displays subtle blue iridescence. The dorsal, pelvic and caudal fins are yellow, while the remaining fins are semi-transparent. Males display these colours most prominently; females are less vibrant and have more uniform colouration.

Axelrod's Rainbowfish are native to New Guinea in the western Pacific, north of Australia. They are found mainly in Sandaun Province, Papua New Guinea. They prefer slow-flowing river sections and backwaters, living among aquatic plants and submerged wood.

These are peaceful, active fish that prefer to live in small groups of 6–8 individuals. They get along well with other non-aggressive species of similar size.

A group of 6–8 fish needs a tank of at least 150 litres. The aquarium should offer both open swimming space and shelter. Natural wood and dense plant clusters, including floating plants, make good shelters. Axelrod's Rainbowfish prefer moderately hard water with a pH above neutral. High temperatures in the range 24–29°C are essential. Wild specimens collected in 1979 came from a tropical stream at 28°C. In the aquarium, such temperatures can increase the risk of hypoxia. Strong aeration and regular removal of organic waste are therefore critical, since decomposition consumes oxygen. The fish are omnivorous and readily accept dried foods. Their diet can include flake, pellet, and frozen or live artemia, daphnia and bloodworm.

This species is omnivorous and readily adapts to dried foods. Their diet may include flakes, pellets, and live or frozen foods such as artemia, daphnia and bloodworm.

Breeding requires a separate spawning tank of at least 40 litres with fine-leaved plants or synthetic spawning substrate. Raising water temperature and heavy feeding of the parents stimulates spawning. Eggs are laid daily in small batches over an extended period and should be transferred to a separate container. Incubation takes up to 12 days; fry then start feeding on infusoria and newly hatched artemia.

The species has good immunity when tank conditions are maintained properly. The main threat comes from bacterial and fungal infections that develop in poor water quality, organic buildup, or stress from overcrowding. Stable water parameters and regular water changes are essential for disease prevention. The fish are sensitive to sudden changes in water chemistry.

When buying, choose active, colourful specimens with clean fins and no signs of damage or coating. Avoid fish with sunken bellies, signs of emaciation, or unusual behaviour such as hanging motionless in a corner. It is best to acquire a group of 6 or more to reduce stress and improve adaptation to the new tank.