Red Rainbowfish

The red rainbowfish is an endangered freshwater fish from a single lake system in Indonesia, where males turn bright red and grow a high back as they age.

It swims in schools in Lake Sentani and its tributaries near Jayapura in Papua, Indonesia, the only place it lives naturally.

The sexes look quite different. Males are bright red, while females are olive brown. Colour shifts with mood, and it is highly variable. Subordinate males do not show the bright colours at all.

It is an omnivore that takes algae, insects, insect larvae and crustaceans, and it may lean a little more towards animal food than most Australian rainbowfishes. Eggs are scattered among clumps of vegetation and take about 7 days to hatch.

The IUCN Red List classes this fish as endangered. The human population around its one natural home is growing fast, and introduced species such as tilapia add to the pressure. Lake Sentani and its tributaries are also home to a related rainbowfish, Chilatherina sentaniensis.