Horseface Loach

The Horseface Loach (Acantopsis choirorhynchos) is a freshwater ray-finned fish in the family Cobitidae, the true loaches. It takes its common name from its unusually long, downward-angled snout, which gives the head a horse-like profile. The species is widespread across mainland Southeast Asia, including river systems in Thailand, Malaysia, and Indonesia. It is a benthic (bottom-dwelling) fish adapted to sandy substrates, where it spends much of its time partially buried. Horseface Loaches are popular in the freshwater aquarium trade for their unusual shape and sand-sifting behavior, though several similar-looking Acantopsis species are frequently confused with one another and sold under the same trade name.

Horseface Loaches are easily recognized by their elongated, torpedo-shaped bodies and long, pointed snouts that curve slightly downward, giving the head a distinctly equine silhouette.

• Coloration: sandy tan to pale olive with a row of dark brown, saddle-like blotches along the back and sides
• Mouth: small, underslung, surrounded by short barbels used to detect food in sand
• Eyes: set high on the head, often with a small erectile spine beneath them (typical of true loaches)
• Fins: low, rearward-set dorsal fin; rounded caudal fin
• Size: reaches 15-20 cm, notably larger and more slender than most other aquarium loaches Look-alike species within Acantopsis are distinguished mainly by subtle differences in blotch pattern and fin ray counts.

Horseface Loaches inhabit lowland rivers, streams, and canals with soft, sandy substrates across Thailand, Peninsular Malaysia, Sumatra, and Borneo. They favor slow-to-moderate flowing water with a sandy or fine-gravel bottom into which they burrow to hide, rest, and ambush prey. Water in their native range is typically warm, ranging from about 22-28°C, with neutral to slightly acidic chemistry. They are rarely found over rocky or heavily vegetated substrates, since their burrowing behavior depends on loose, diggable sand. Seasonal flooding in their range temporarily expands available habitat, and the species tolerates a range of dissolved oxygen levels typical of tropical lowland waterways.

Horseface Loaches are primarily nocturnal and spend daylight hours buried in sand with only their eyes and snout tip exposed. At night they emerge to forage across the substrate, using their sensitive barbels to locate small invertebrates, worms, and organic debris, which they sift from mouthfuls of sand before expelling it through their gills. They are generally peaceful and non-territorial, often loosely grouping with others of their kind rather than forming tight schools. Like other loaches, they can gulp atmospheric air and pass it through their gut as an accessory breathing mechanism in low-oxygen water. Spawning is not well documented in the wild but is believed to follow seasonal flooding patterns.