Patella Hillstream Loach

Sewellia patella is named for the kneecap-like outline of its broadly rounded pectoral fin disc when viewed from above. This small hillstream loach from the rivers of Vietnam is one of the more delicately built members of its genus, reaching barely 5.5 cm, but its adhesive capability and rheophilic adaptations are as impressive as those of its larger relatives. Its patterning is subtler than some Sewellia — pale buff with fine dark spotting — which makes it blend beautifully with the granitic substrates of its home streams.

Care requirements mirror the broader Sewellia template: cool, highly oxygenated, fast-flowing water with very low organic waste. This species is particularly sensitive to temperature creep and should be kept at or below 24 °C at all times. It does best in a species or near-species tank where strong flow is maintained throughout the aquarium without compromise.

In groups of four or more, S. patella interacts socially and individuals can often be seen resting in loose clusters on flat stones, particularly after feeding on a freshly placed algae wafer.

Water: 18–24°C, pH 6.5–7.5, GH 4–15, KH 2–8; high flow with surface agitation; temperature stability is critical — avoid fluctuations above 24°C. Tank: 80 L minimum; smooth flat stones essential; minimal silt and excellent mechanical filtration to maintain clarity. Feeding: Biofilm, diatoms, and green algae; offer spirulina wafers and blanched greens; avoid protein-heavy foods. Breeding: Similar to other Sewellia; may spawn under flat stones when cooled and given increased flow; fry extremely small. Compatibility: Very peaceful; best kept with other cool-water hillstream species or small, non-boisterous dither fish.