Chen's Pseudogastromyzon

Pseudogastromyzon cheni is one of the most commonly encountered hillstream loaches in the trade from southern China, collected from clear fast-flowing streams in Guangdong and Fujian provinces. Its warm brown-blotched patterning is less flamboyant than some of its hillstream relatives, but it more than compensates with its hardiness, active personality, and eagerness to feed. It is often recommended as the best introductory hillstream species for newcomers to the genre.

The species adapts well to aquaria provided the keeper maintains adequate flow and cool water. It is less sensitive to temperature than Vietnamese species, tolerating short periods up to 26 °C without immediate harm, though temperatures above this should be avoided. P. cheni is a tireless algae grazier that will keep glass and décor impressively clean given sufficient light to grow algae for it to harvest.

In groups of five or more, Chen's Pseudogastromyzon displays interesting social behaviour, establishing loose hierarchies and occasionally competing with brief lateral displays for access to prime feeding locations on flat rock surfaces. These interactions are harmless and add considerable interest to the aquarium.

Water: 18–24°C, pH 6.5–7.5, GH 4–15, KH 2–8; moderate to strong flow essential; tolerates slightly warmer conditions than Sewellia but cooler is always better. Tank: 70 L minimum; smooth pebbles and flat stones; excellent filtration to keep nitrates below 20 ppm; some algae growth on stones is desirable. Feeding: Biofilm and algae; spirulina wafers, algae tabs, blanched greens; will also accept small amounts of frozen daphnia. Breeding: Has been bred in captivity; eggs deposited under flat stones; condition adults with water changes and moderate flow increase. Compatibility: One of the best hillstream species for community biotopes; compatible with danios, white cloud minnows, and other cool-water species.