Forktail Blue Eye

Pseudomugil furcatus

Also known as: Forktail rainbowfish, Furcata rainbowfish, Forktail blue-eye

Water Parameters

• Temperature: 23–28°C
• pH: 7–8
• Hardness (GH): 143–268 ppm (8–15 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A jewel-bright little blue-eye from New Guinea, and the showiest of the group commonly kept beside the pacific and gertrude's blue-eyes. Its body is a pale yellow-green, but the fins are the draw: bright lemon-yellow edged in black on the dorsal, anal, and deeply forked tail, which the males flare and fence with in tireless, harmless display. Best in a group of eight or more in a planted, mature nano tank, it is genuinely safe even with baby shrimp thanks to a tiny mouth, and its liking for hard, alkaline water suits much of Australian tap supply. Short-lived like most blue-eyes and happiest on small live or frozen foods, it is a lively, colourful, low-aggression centrepiece for a dedicated small setup.

Tankmates

A small, peaceful, surface-loving rainbowfish relative and a natural companion to the pacific and gertrude's blue-eyes, sharing their gentle temperament and need for a group of at least eight to draw out the males' constant fin-flaring displays. Genuinely shrimp-safe thanks to a tiny mouth, and far too small to threaten any tankmate, but equally vulnerable to being eaten, so it belongs strictly in a nano community of similarly tiny, peaceful species. Its preference for hard, alkaline water suits much of Australia's tap supply and pairs it well with the other blue-eyes. Provide a planted, mature, gently-filtered tank and small foods.

Compatible with

• Pacific Blue Eye
• Gertrude's Blue Eye
• Celestial Pearl Danio
• Ember Tetra
• Pygmy Corydoras
• Cherry Shrimp
• Otocinclus

Avoid keeping with

• Betta
• Angelfish
• Large Cichlids
• Fin Nippers
• Any Larger Fish

Common Problems

• short lifespan (typically 2 to 3 years)
• preference for small live or frozen foods
• predation by any larger tankmate
• muted display in groups smaller than 8

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20