Chilatherina is a genus of rainbowfish in the family Melanotaeniidae, endemic to New Guinea, with atlas records from Indonesia and Papua New Guinea only. The 11 species covered here range from about 2.5–4.5 in and share the deep-bodied, laterally compressed rainbowfish shape, with two closely spaced dorsal fins and, in breeding males, a pronounced arch to the back. They inhabit clear highland and lowland streams, rivers, and lakes across the island, often in cooler, well-oxygenated water than many of their Australian relatives favor.
Chilatherina is a genuinely popular aquarium genus: males color up vividly, often in red, orange, or blue, and display those colors to each other in active courtship, making species such as Chilatherina bleheri, Bleher's rainbowfish, Chilatherina campsi, the highlands rainbowfish, and Chilatherina fasciata, the barred rainbowfish, sought-after community fish for planted, well-aerated tanks. They are egg-scattering spawners among fine-leaved plants or mops.
The conservation picture is concerning for a genus this well known in the hobby: 3 species are Endangered and one Critically Endangered, with 2 more Vulnerable and only 4 rated Least Concern; 6 of the 11 atlas species are flagged in the atlas's CARES conservation-priority list, underscoring how vulnerable New Guinea's restricted stream and lake systems have become to habitat disturbance and introduced species.