Hemipsilichthys gobio

Hemipsilichthys gobio is a robust and somewhat goby-like loricariid from the coastal rivers of southeastern Brazil's Atlantic Forest zone. The genus Hemipsilichthys includes several species of moderately sized, thickset loricariids adapted to fast-flowing rocky rivers draining the steep Atlantic escarpment. H. gobio is the type species of the genus and the most widely known, reaching up to 7 cm — larger than most species in this catalogue.

In nature, H. gobio inhabits fast-flowing rivers with rocky substrate — the same type of habitat as hillstream loaches in Asia, but in the Atlantic Forest of southeastern Brazil. The species clings tightly to smooth boulders in strong current, using its robust adhesive disc and flattened body to resist displacement, while scraping adherent periphyton and diatoms from rock surfaces. Water in these rivers is clear, well-oxygenated, moderately hard, and cool to moderately warm.

For aquarists, H. gobio requires a setup with meaningful water movement — a standard still or gently filtered planted tank will not suffice. Strong current from a powerhead or high-flow canister return, smooth rocks, and clear, well-oxygenated water are essential. Its larger size than typical otocinclus-alliance species means it has a greater grazing impact on algae but also requires more supplemental food. An excellent advanced species for the Atlantic Forest biotope aquarium.

Water: Soft to moderately hard at pH 6.0–7.5 and 18–24°C; strong current and very high dissolved oxygen are non-negotiable for this rheophilic species. Tank: 80 litres minimum with smooth rocks, powerful directional flow, and minimal organic detritus. Feeding: Periphyton on rocks primary; supplement generously with algae wafers placed in current and blanched vegetables. Breeding: Not documented in captivity. Compatibility: Peaceful but requires fast-flowing conditions unsuitable for most planted community fish; pair with other rheophiles.