Hillstream Loach

Hillstream loaches solve the "stay put in fast water" problem with a different toolkit than most current-loving fish: their pectoral and pelvic fins splay out and fuse at the base into a broad suction disc, pinning the entire body flat against the current instead of relying on a sucker mouth alone. That's exactly why a placid, slow-flow tank leaves one listless — replicate the riffle it evolved for and it stays glued to the glass and rockwork, constantly grazing.

Care level: Moderate · Temperament: Peaceful · Max size: ~3" · Min tank: 20 gal, strong flow · Diet: Herbivore, algae + wafers