Red rainbowfish
A bright red freshwater fish from Lake Sentani, Indonesia.
The red rainbowfish is a small, colourful species native to Lake Sentani in Indonesia. Males turn vivid red with age, while females remain olive brown. It is endangered in the wild due to habitat pressure but thrives in home aquariums worldwide.
- Males turn bright red and grow a high back with age.
- Endemic only to Lake Sentani and its tributaries in Indonesia.
- Listed as endangered by the IUCN due to habitat loss.
- Eggs hatch after approximately seven days in vegetation.
- Common in aquariums despite being rare in the wild.
What it is
This species belongs to the family Melanotaeniidae, known as Australian rainbowfishes. It displays strong sexual dimorphism. Adult males develop a high back and turn a brilliant red colour. Females are olive brown. Both sexes can change their hue based on mood, though subordinate males rarely show bright tones. The fish grows to a maximum length of 15 cm, but most individuals reach only about 12 cm in captivity or the wild.
Where it lives
The red rainbowfish is endemic to a single location. It lives only in Lake Sentani and its connecting tributaries. This water system is situated near Jayapura in the Papua province of Indonesia. The species shares this limited geographic range with a relative, Chilatherina sentaniensis. Its confinement to one lake system makes it particularly vulnerable to local environmental changes.
How it lives
In terms of diet, this fish is an omnivore. It consumes both plant and animal matter. Observations suggest it may be slightly more carnivorous than other members of its group. In home tanks, it accepts most standard commercial foods without issue. Social hierarchy affects appearance, as lower-ranking males do not display the vivid red colours seen in dominant individuals.
Breeding and life cycle
Reproduction involves scattering eggs rather than guarding them. Adults release their gametes among dense clumps of aquatic vegetation. The eggs adhere to the plants and develop there. Incubation lasts approximately seven days before the young hatch. This method allows for easy breeding in captivity, which has helped maintain the population outside its native habitat.
Fish and people
Aquarists value this species for its striking male colouration. It is common in the global aquarium trade because it breeds readily in tanks. Despite its popularity in homes, it faces severe threats in nature. Conservation efforts focus on captive breeding to prevent total loss, as wild numbers decline due to human activity around its only known habitat.
Status and threats
The International Union for Conservation of Nature lists this fish as endangered. Its survival is threatened by a rapidly growing human population near Lake Sentani. Introduced species, such as tilapia, also compete with or prey upon the native stock. These pressures endanger the entire wild population, which exists in just one lake system.
Questions people ask about Red rainbowfish
Where does the red rainbowfish live in the wild?
It is found only in Lake Sentani and its tributaries near Jayapura in Papua, Indonesia. It does not occur naturally anywhere else in the world.
Why is the red rainbowfish considered endangered?
Its status is endangered because of the increasing human population around Lake Sentani. Introduced species like tilapia also threaten its survival in its native habitat.
How large do red rainbowfish grow?
They can reach a maximum length of 15 cm. However, they typically attain a smaller size of around 12 cm in both wild and captive environments.
Good reading and sources
- Red rainbowfish on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Red rainbowfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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