Forktail Blue-Eye Rainbowfish

Native to clear, slow-moving streams in Papua New Guinea, Pseudomugil furcatus is one of the most visually striking fish you can put in a nano planted tank. Despite maxing out around 4cm, males put on a serious show. Their fins are edged in vivid yellow with elongated rays giving that distinctive forked look, and those electric blue eyes catch light in a way that photographs don't really do justice to. Females are plainer, as is typical with this genus, but they're still attractive little fish with a subtle iridescence.

They come from clean, well-oxygenated water with moderate hardness, so they're not as fussy as some of their Pseudomugil cousins. A pH anywhere from 6.0 to 8.0 suits them, and they adapt reasonably well to a range of moderately hard water conditions. Temperature-wise, mid-to-upper 20s Celsius keeps them active and healthy. They do not tolerate poor water quality well at all, so regular water changes are non-negotiable.

Feeding is where beginners sometimes stumble. Their mouths are tiny, and standard tropical flakes are often too large. They really need micro foods like baby brine shrimp, daphnia, micro pellets, or quality crushed flake. Frozen cyclops and micro worms go down well too. Variety keeps their colors sharp.

In a well-planted nano setup, a group of these fish is genuinely mesmerizing. Males constantly flare, circle, and display to one another in a low-stakes rivalry that never really turns nasty. If you want to see what a small tank can look like when it's done right, searching out community builds featuring forktail blue-eyes is worth your time.