Acantopsis dialuzona

The Horseface Loach is a unique, eel-like bottom-dweller known for its distinct long snout and fascinating habit of burrowing completely into the substrate. As an omnivore, its diet should consist of various sinking foods that reach the bottom of the aquarium, such as pellets, wafers, and occasional frozen or live treats. This species thrives when kept in small groups, as they are naturally social and feel more secure with companions. They are generally peaceful but are considered to have a moderate care difficulty, making them better suited for aquarists with some experience.

One of their most characteristic behaviors is digging and rooting through the substrate, which can uproot loosely planted aquarium plants. They spend almost all their time at the bottom of the tank, searching for food or hiding. Potential owners should be aware that these loaches can be surprisingly good jumpers, so a securely fitted lid on the aquarium is essential to prevent them from escaping. With proper care in a suitable environment, these interesting fish can live for several years, providing endless fascination with their unusual appearance and behavior.

The Horseface Loach, a native of freshwater systems in Asia, is a specialized benthic fish that brings unique behaviors to the home aquarium. Its natural habitat consists of streams and rivers with noticeable water movement, a condition that should be replicated in captivity with moderate water flow to ensure adequate oxygenation and to mimic its environment. Due to its medium difficulty rating, this species is best cared for by aquarists who can provide a stable and well-maintained setup.

Physically adapted for a life on the substrate, its most critical care requirement is the choice of substrate itself. A soft, fine-grained sand is mandatory, as these loaches spend a significant portion of their time sifting through it for food and burrowing to hide. Coarse gravel can damage their delicate snouts and underbellies, leading to stress and infection. This burrowing habit, while natural and necessary for their well-being, means that rooted plants may be uprooted unless they are well-established or protected.

As a shoaling species, the Horseface Loach should never be kept alone. A group of five or more is recommended to allow for natural social interaction, which reduces stress and encourages more active behavior. In an appropriately sized aquarium, they will coexist peacefully with other similarly-sized and tempered fish that occupy the middle and upper water columns. As omnivores, their diet must be varied. High-quality sinking pellets and wafers should form the staple, supplemented regularly with frozen and live foods to ensure balanced nutrition. Because they are slow swimmers and deliberate feeders, ensure that food reaches them past more boisterous tank mates. They exhibit a moderate metabolism and produce a moderate amount of waste, contributing a noticeable bioload to the aquarium that necessitates a robust and efficient filtration system. Finally, their known ability to escape the tank requires that the aquarium has a tight-fitting lid at all times.

Acantopsis dialuzona is a validated species within the family Cobitidae, commonly referred to as true loaches. This fish is classified under the order Cypriniformes and is native to freshwater riverine ecosystems in Asia. Its morphology is distinctly anguilliform, characterized by an elongated, eel-like body perfectly suited for its benthic and fossorial lifestyle. This body shape minimizes water resistance, allowing it to navigate through substrate and currents efficiently.

Ecologically, A. dialuzona functions as a benthic omnivore, playing a role in bioturbation. Its feeding strategy involves sifting through soft sediment to find invertebrates, detritus, and plant matter. This constant rooting and digging aerates the top layer of the substrate, contributing to nutrient cycling within its habitat. Its physiological requirements point to an adaptation to environments with moderate water flow, which typically have higher levels of dissolved oxygen, correlating with its medium oxygen consumption rate. It is a strictly freshwater species with very low tolerance for salinity. It thrives within a specific range of pH and water hardness, indicating sensitivity to significant fluctuations in water chemistry.

From a husbandry perspective, its moderate metabolism, waste production, and calculated bioload factor are key data points for maintaining it in closed aquatic systems. The species' IUCN status is listed as Least Concern (LC), suggesting that its populations are currently stable across its native range. However, like many riverine species, it is susceptible to habitat degradation from pollution, damming, and substrate extraction. Breeding in captivity is exceptionally difficult and is noted to require special conditions, often involving hormonal induction, which mimics the complex environmental triggers of its natural spawning cycle.

Breeding the Horseface Loach in a home aquarium is an exceptionally challenging endeavor and is rarely achieved without professional intervention. The species requires specific and complex environmental triggers to induce spawning, making natural reproduction in captivity a rare event. Success typically relies on simulating seasonal changes found in its native Asian habitats and often involves the use of hormonal treatments.

There are no prominent or reliable external characteristics to differentiate males from females, a challenge known as a lack of sexual dimorphism. This makes selecting a viable breeding pair a matter of chance, further complicating breeding efforts. For any attempt, it is best to start with a large, healthy, and well-established group to increase the probability of having both sexes present.

To condition the fish for a potential spawning attempt, a diet rich in protein and fat is essential. This includes frequent feedings of high-quality live and frozen foods to help them build the necessary energy reserves for gamete production. A dedicated breeding aquarium is a necessity. This tank should be set up to meticulously replicate their natural environment, featuring a deep bed of very fine, soft sand, moderate water flow, and pristine water parameters within their ideal range. Simulating an environmental trigger, such as a slight and gradual temperature drop followed by a rise, combined with water changes that soften the water, may help encourage spawning readiness, though success is not guaranteed.

If spawning were to occur, it would likely involve the scattering of eggs over or into the substrate. The adults would show no parental care and should be removed promptly to prevent them from consuming the eggs. Rearing the fry would present its own set of difficulties. The fry would be extremely small and would require microscopic foods such as infusoria, rotifers, or liquid fry food for their initial stages of life before graduating to newly hatched brine shrimp. A bare-bottom tank or one with a very thin layer of sand would be beneficial for monitoring the fry and ensuring they can find food.