Chinese Butterfly Loach

Beaufortia kweichowensis, the Chinese Butterfly Loach or Butterfly Hillstream Loach, is the archetypal hillstream loach for most aquarists — the species that introduces thousands of hobbyists each year to the rheophilic world. Its wide, spread pectoral and pelvic fins give it a butterfly-like silhouette from above, and its flattened underside allows it to cling to glass, rocks, and other surfaces in powerful current. Patterning varies between individuals, ranging from dark reticulated to broadly mottled warm brown and cream.

Originally from Guizhou province in southwestern China, it inhabits cool, fast-flowing, highly oxygenated hill streams flowing through karst limestone landscapes. This background means it appreciates slightly harder, more alkaline water than many other hillstream species — a pH of up to 7.5 and moderate hardness are acceptable. Water temperature should remain cool, with the ideal range of 18–24 °C essential for long-term health.

B. kweichowensis is one of the few hillstream loaches bred consistently in captivity, and captive-bred stock is now available. In the aquarium it is hardy, adaptable, and long-lived when properly maintained, with specimens frequently reaching eight years or more. It is mildly territorial with conspecifics but interactions rarely exceed brief lateral posturing displays.

Water: 18–24°C, pH 6.5–7.5, GH 5–15, KH 3–10; the most tolerant of commonly available hillstream loaches, but still requires strong flow and oxygenation. Tank: 80 L minimum; smooth boulders and flat stones; tolerates some algae on glass which it will harvest; clean substrate to prevent detritus build-up. Feeding: Biofilm, diatoms, and green algae; supplement with spirulina wafers, algae tabs, and blanched greens; a well-lit tank promotes natural algae growth. Breeding: One of the most successfully captive-bred hillstream loaches; condition with cool water changes and increased flow; eggs under flat rocks; fry need biofilm. Compatibility: Excellent beginner hillstream species; compatible with danios, White Cloud Mountain Minnows, and other cool-water community fish.