Sicyopus zosterophorus
Sicydiine gobies, or “cling gobies,” are a subfamily (Sicydiinae) of around 80–90 species in eight genera, more than half described only in the last twenty years. Every species is amphidromous: adults live and spawn in fast, clear freshwater streams, but the tiny hatchlings are swept out to sea, where they spend a planktonic larval phase before returning to fresh water as post-larvae — often in a synchronised pulse the day after a full moon — and migrating back upstream, sometimes climbing waterfalls along the way using a sucking disc formed from fused pelvic fins. Most species graze algae and biofilm from rock surfaces using a distinctive fleshy sac of replacement teeth above the upper jaw, and males in breeding condition are typically brilliantly coloured, in sharp contrast to drabber females. All Australian cling gobies are protected species — look, but don’t touch.
Species Summary
Photographed at multiple New Guinea localities including Misima and Goodenough Islands, Sicyopus zosterophorus has also reached the German aquarium hobby via wild-caught imports from Biak Island, off West Papua.
In the Aquarium
A detailed husbandry account describes Sicyopus zosterophorus kept alongside Stiphodon atratus in a 200 litre tank furnished with granite boulders and Cryptocoryne, with the two genera showing distinctly different feeding styles: Stiphodon a dedicated algae grazer using fine, comb-like scraping teeth, while Sicyopus proved more opportunistic, even eating crushed snails. Both maintained a roughly 10 cm personal-space radius around themselves with little serious fighting, though no breeding was achieved.
Compiled for Home of the Rainbowfish from ANGFA sources: C. Mailliet, “Cling gobies from Biak”, Fishes of Sahul 20, 2006, pp. 284–287; G. R. Allen, “Unexplored islands of Papua New Guinea”, Fishes of Sahul 17, 2003, pp. 926–948.