Blue Belly Goby

The blue-belly goby is a small, peaceful freshwater goby recorded from freshwater streams in Taiwan, southern Japan, Guam, and Palau. Males develop a striking iridescent blue ventral region during breeding condition, making them a visually rewarding species for the dedicated aquarist. Adults reach only 3.5 cm standard length, making them suitable for smaller well-maintained setups.

This species is an obligate grazer of biofilm and algae in nature, so the diet must reflect this — provide ample established surfaces with algae growth, supplemented with spirulina-based foods, blanched vegetables, and occasional small live or frozen foods. A tank with a base of at least 60 by 30 cm (about 54 litres) is recommended, with strong water flow to replicate their natural stream habitat. The substrate should be fine sand or smooth gravel, and a secure lid is essential as these fish are known jumpers.

Water parameters should be 22-28°C, pH 6.5-7.5, with moderate hardness. Males can be loosely territorial toward one another, so a group composition of one male with multiple females, or a group of six or more in a larger tank, works best. They are peaceful with other small, non-aggressive species and make excellent additions to hillstream biotope aquaria alongside similar-sized gobies and rheophilic fish.