Cobalt Blue Goby

Geographical Origin and Habitat: Indonesia, Philippines, New Guinea, and Solomon Islands. Inhabits clear, fast-flowing coastal streams with rocky beds and high oxygen levels.

Taxonomy and Morphology: Member of the family Gobiidae, subfamily Sicydiinae. Slender cylindrical body with fused pelvic fins acting as a suction disk to hold onto rocks in strong currents. Reaches 5 cm.

Social Behavior: Peaceful and active. Males establish small territories on flat stones and display intense coloration during harmless territorial disputes or courtship.

Coloration and Sexual Dimorphism: Pronounced sexual dimorphism. Adult males display brilliant metallic cobalt blue or electric blue on their upper body. Females are cryptically colored, grey-brown with two dark stripes.

Aquarium Setup: Demands a river manifold system or strong powerheads to simulate rapids in a tank of at least 60 liters. Use smooth pebbles and boulders under bright lighting to grow algae. Tight lid required.

Diet and Feeding: Obligate biofilm grazer (Aufwuchs). Feeds on natural algae and cyanobacteria. Supplement with high-quality spirulina wafers and repashy gel, but stable natural algae growth is mandatory.

Water Quality: Crystal clear, highly oxygenated water. Temperature 22-28 °C, pH 6.5-7.5, GH 2-12, KH 1-8. Nitrates must be kept minimal.

Compatibility and Cohabitation: Peaceful. Suitable for hillstream setups with other Stiphodon, small danios, devarios, or freshwater shrimp. Avoid large or aggressive tankmates.

Aquarium Breeding: Amphidromous life cycle. Spawns in freshwater, but larvae drift to the sea and require marine conditions before returning to freshwater as post-larvae.

Risks and Diseases: High starvation risk in newly established tanks. Exceptional jumpers, capable of climbing glass panes.