About the Cobalt Blue Goby
name: cobalt blue goby (stiphodon semoni)
max size: up to 2 inches
water parameters: pH 6.5-7.5, temperature 72-80°F, soft to moderately hard water; requires clean, highly oxygenated freshwater
diet: primarily herbivorous and biofilm-grazing – feeds on soft algae, diatoms, biofilm, and microorganisms growing on rocks; supplement with spirulina-based foods, algae wafers, and occasional small live or frozen foods such as daphnia and brine shrimp
temperament: peaceful toward other fish, although males can be territorial toward other gobies; generally suitable for small groups when adequate space and grazing surfaces are provided
tank setup: mature, stream-style aquarium with smooth rocks, rounded gravel, strong water circulation, and excellent filtration; bright lighting encourages natural algae and biofilm growth, while rocks and crevices provide hiding places and individual territories
compatibility: ideal with peaceful fish that appreciate flowing, well-oxygenated water, such as small danios, rasboras, and hillstream loaches; avoid aggressive bottom dwellers, large predatory fish, and species that require slow-moving water
behavior: spends much of its time perched on rocks, grazing on algae and biofilm using its specialized mouth; males frequently display their vibrant blue coloration while defending preferred feeding territories and interacting with other gobies
fun fact: male cobalt blue gobies can develop stunning metallic cobalt-blue coloration that shimmers under aquarium lighting. Their fused pelvic fins form a powerful suction disc, allowing them to cling securely to rocks in fast-flowing streams. In the wild, their larvae drift into the ocean before returning to freshwater as juveniles, making them extremely difficult to breed in captivity.
