Irian Red Rainbow

Irian Red Rainbow (Glossolepis incisus) is one of the most dramatically colored rainbowfish available. Fully mature males develop a deep, saturated salmon-red to crimson body that covers the entire fish — from nose to tail — with an iridescent quality that shifts between red, orange, and even faintly gold depending on the light. The high, arched back of adult males gives them an impressive, almost circular silhouette.

Feeding & Care Tip: Sera Vipan Tropical Flakes and Hikari Micro Pellets make excellent daily staples. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Bloodworms to develop and maintain the deep red coloration. Crush flakes and soak pellets for juveniles, which are considerably paler than adults and can look almost silver — patience is required as full color develops only in mature males.

Native to Lake Sentani near Jayapura in West Papua, Indonesia — Irian Jaya is the former name for the Indonesian portion of New Guinea, giving the fish its common name. Males take 12–18 months to develop their full red coloration. Females remain olive-brown and silver throughout their lives — a striking sexual dimorphism. The species is listed as Vulnerable on the IUCN Red List.

Keep in groups of at least six with a mix of males and females. Males compete actively with impressive fin displays and body darkening, but aggression is rarely harmful in a properly sized group. A larger tank with multiple males produces the most intense color as males display constantly to one another.

A well-planted aquarium with open swimming space in the center replicates the rainbowfish's natural riverine habitat. These are active, fast-swimming fish that appreciate length more than height — a longer tank allows them to build up speed and display properly. Good filtration and regular partial water changes are important, as rainbowfish are sensitive to deteriorating water quality. Avoid very small or slow-moving tankmates that may be outcompeted at feeding time.

Care & Ideal Parameters