Panda Loach (Yaoshania pachychilus)

Yaoshania pachychilus is a gastromyzontid hillstream loach endemic to the Guangxi Zhuang Autonomous Region of southeastern China, where it inhabits clear, fast-flowing, oxygen-rich mountain streams with rocky and pebbly substrates. First described in 2011, it rapidly became one of the most sought-after hillstream loaches in the aquarium hobby due to its extraordinary bold black-and-white panda pattern.

Juvenile and young adult specimens are particularly strikingly marked: alternating bold black and white to yellowish-white bands encircle the body from behind the head to the tail base — a pattern almost identical to a giant panda's coloration. As specimens mature, some individuals may develop darker, less contrasting coloration, though many retain the bold juvenile pattern in good conditions.

The body is strongly dorso-ventrally flattened with broad, horizontal pectoral and pelvic fins forming a wide base — the classic hillstream loach body plan adapted for life in powerful current. The underside features a weak suction disc formed by modified lips and fin positioning that allows the fish to cling to smooth surfaces against strong flow.

Yaoshania pachychilus grazes on algae, biofilm, and micro-organisms scraped from rock surfaces using the specialized rasping mouth. It is entirely benthic, spending all its time on the substrate and rockwork.

Panda Loaches are exacting in their requirements. Maintain pH 6.5–7.5, hardness 5–12 dGH, and temperatures 15–22°C — cool temperatures are essential and they are stressed by sustained temperatures above 23°C. High oxygen levels and strong, turbulent current (powerheads, strong filter returns, spray bars) are mandatory.

A minimum 80-liter aquarium with smooth rocks, pebbles, slate, and very strong water movement provides suitable conditions. Bright lighting encourages algae and biofilm growth on rocks — the primary food. Use a fine sand or bare bottom substrate.

Feed primarily through natural algae and biofilm development on rocks. Supplement with quality algae wafers, sinking spirulina tablets, and blanched vegetables (zucchini, spinach, cucumber). Ensure supplemental food reaches the bottom past stronger current zones where they rest.

Panda Loaches may be mildly territorial with conspecifics in small tanks. In aquariums of 150+ liters with multiple distinct rock territories, groups of 4–6 can coexist. Compatible with other cool-water, high-oxygen species: White Cloud Mountain Minnows, hillstream loaches, and cool-water danios.

Water changes of 30–40% twice weekly with temperature-matched cool water maintain the pristine, oxygen-rich conditions this species requires. They are sensitive to warm water and water quality deterioration.