Fish
Turquoise Rainbowfish
Melanotaenia lacustris · also called lake kutubu rainbowfish
A vivid turquoise-blue body catches the light as a male turquoise rainbowfish schools with others of its kind, a species found naturally in only a single lake in Papua New Guinea, leaving its entire wild population dependent on the health of that one body of water.
Overview
The turquoise rainbowfish, Melanotaenia lacustris, is a Vulnerable fish found naturally only in Lake Kutubu, Papua New Guinea. Its striking turquoise colouring, single-lake natural range, and schooling behaviour make it one of the most visually vivid yet geographically vulnerable rainbowfish species kept in aquariums.
A species tied to one lake
With its entire natural population confined to a single lake, the turquoise rainbowfish has essentially no backup range to fall back on if conditions there decline, a precarious situation shared by several other rainbowfish species restricted to individual water bodies in New Guinea.
Status
Vulnerable, with its entire wild population confined to Lake Kutubu in Papua New Guinea and exposed to habitat change and introduced species.
Turquoise Rainbowfish: common questions
How restricted is the turquoise rainbowfish's natural range?
It is found naturally in only a single lake, Lake Kutubu in Papua New Guinea, making it one of the most range-restricted rainbowfish species and especially vulnerable to any change in that one body of water.
Why is the turquoise rainbowfish vulnerable?
Its entire wild population depends on a single lake, so any decline in water quality or the introduction of non-native species there could have an outsized impact on the species as a whole.
Do male and female turquoise rainbowfish look different?
Yes, males display deeper, more saturated turquoise colouring and a taller body shape, while females are comparatively plainer.
Should turquoise rainbowfish be kept alone or in groups?
In groups; it is a schooling fish that shows more natural behaviour and more vivid colouring when kept with others of its own kind.