Semon's Stiphodon Goby

Stiphodon semoni is a widely distributed Pacific island hillstream goby ranging across Indonesia and Melanesia, typically collected from highland sections of rivers well above tidal influence. Males display a warm orange body with blue-tinged head and flanks, complemented by vivid finnage colouration during courtship and territorial display. The species was named in honour of the German zoologist Richard Semon and has been known to science since the late nineteenth century.

In aquaria, S. semoni requires the same fundamental conditions as other Stiphodon species: strong, clean, well-oxygenated flow over smooth rock, neutral to alkaline pH, and moderate hardness. It is marginally more temperature-tolerant than its Taiwanese relatives, thriving towards the warmer end of the Stiphodon range. Its amphidromous life cycle prevents captive breeding with current techniques, so all specimens are wild-caught.

Semon's Stiphodon is a reliable biofilm and microalgae grazer that will methodically clean smooth rock surfaces throughout the day. In a well-lit aquarium with strong flow and nutrient-controlled water chemistry, sufficient microalgae growth to supplement prepared foods can be maintained on smooth boulders.

Water: 22–26°C, pH 7.0–8.0, GH 6–18, KH 4–12; strong flow and high dissolved oxygen essential; moderately hard, slightly alkaline water preferred. Tank: 60 L minimum; smooth boulders with established green microalgae films; powerful flow from powerhead; no stagnant zones. Feeding: Herbivore — grazes microalgae and biofilm; supplement with spirulina wafers, Repashy Soilent Green, and blanched greens. Breeding: Amphidromous; captive breeding requires marine larval stage — not feasible in standard freshwater aquaria; all trade fish are wild-caught. Compatibility: Males mildly territorial with each other; peaceful toward other species; do not keep with boisterous or fin-nipping tankmates.