Acantopsis dialuzona

The Horseface Loach, Acantopsis dialuzona, is a fascinating but demanding addition to a specialized aquarium setup. Its most defining characteristic is its burrowing nature. A fine sand substrate of at least two inches deep is not just a preference but a requirement for their welfare. The sand allows them to engage in natural foraging behavior and provides them with security by allowing them to bury themselves, a behavior often observed during the day. Sharp gravel or coarse substrate will damage their sensitive snout and barbels, leading to stress and infection. Given their classification as 'plant rooter' and 'tank escape artist', aquascaping and tank security require careful planning. Robust plants like Anubias or Java Fern attached to driftwood are recommended over rooted stem plants, which will likely be uprooted. A tight-fitting, weighted lid is essential to prevent escapes.

Socially, their behavior is complex. They are shoaling fish that thrive in the company of their own kind, and a group of five or more is recommended to observe their natural interactions and reduce stress. However, within this group, they can be territorial, especially in cramped quarters. A large footprint tank is more important than height to provide enough bottom space for each loach to establish a small territory, mitigating potential squabbles. When selecting tankmates, prioritize active, mid-to-top dwelling species like larger rasboras or barbs. Avoid slow-moving bottom-dwellers like Corydoras, as the large and sometimes boisterous Horseface Loach may outcompete them for food and cause stress with their constant digging. Feeding should cater to their omnivorous, bottom-feeding habits, with a high-quality sinking pellet or wafer as a staple, supplemented regularly with frozen or live foods like bloodworms and brine shrimp to ensure a balanced diet.

Acantopsis dialuzona is a member of the Cobitidae family, characterized by its anguilliform, or eel-like, body morphology, which is an adaptation for its benthic and fossorial lifestyle. This species exhibits specialized behaviors directly linked to its anatomy and native ecology. The elongated rostrum, which gives the species its common name, is used to sift through fine substrate to locate food, which in situ consists of micro-crustaceans, insect larvae, and organic detritus. The mouth is sub-terminal and equipped with sensitive barbels for chemoreception in low-visibility conditions. A key husbandry requirement is the provision of a soft, deep sandy substrate to facilitate their innate burrowing behavior, which is crucial for psychological well-being and stress reduction. Failure to provide this can lead to physical harm and chronic stress.

Physiologically, A. dialuzona has a moderate metabolic rate and bioload factor. Its large adult size necessitates a significant aquarium volume, not only to dilute waste but also to accommodate its social and territorial needs. They are a shoaling species but exhibit intraspecific territoriality; thus, a large benthic surface area is critical for maintaining a stable social hierarchy in a group and preventing chronic aggression. Tankmates must be chosen with care to avoid interspecific competition for benthic resources. Breeding in captivity is exceedingly rare for hobbyists as this species requires specific environmental triggers for spawning, likely tied to seasonal monsoons in its native Southeast Asian riverine habitats. Commercial aquaculture relies on hormonal induction (e.g., gonadotropin-releasing hormone analogues) to achieve reproduction, a method not feasible in a home setting. Its IUCN 'Least Concern' status suggests a stable wild population, though localized threats from habitat degradation and collection for the aquarium trade persist.