Horseface Loach Care: Tank Size, Diet & Substrate

Species Overview#

Horseface loaches (Acantopsis dialuzona) are slender, sand-dwelling fish from the river basins of Southeast Asia, named for the elongated, downward-sloping snout that gives them an unmistakable equine profile in side view. They glide along the substrate like a small armored snake, then vanish — burying themselves up to the eyes in fine sand within seconds, often surfacing several feet from where they went under. Hobbyists who keep them describe the experience as "owning a fish that's mostly an idea": present, important to the tank's ecology, but rarely fully visible.

The species has been in the aquarium trade for decades under several names — including the synonym Acantopsis choirorhynchos, the trade name "banana loach" (a nod to its slightly curved shape), and the descriptive "long-nosed loach." Despite the variable labels, the care needs are consistent and forgiving as long as one rule is honored: the substrate must be soft, fine sand. Get that right and they live for years as the cleanup-crew foundation of a peaceful, planted, mid-sized community tank.

Adult size

8 in (20 cm)

Lifespan

8-10 years

Min tank

55 gallons

Temperament

Peaceful sand-burrower

Difficulty

Intermediate

Diet

Carnivore-leaning omnivore

The "Long-Nosed" Aesthetic: Identifying Acantopsis dialuzona#

The horseface loach is unmistakable once you see the head profile in side view. The snout extends well in front of the mouth, sloping down at a steep angle and tapering to a fine point — the same shape as a horse's face from the eye to the muzzle. The body is pale tan to soft gold along the back, fading to a creamy white belly, with a row of dark blotches along the lateral line and irregular speckling across the dorsal surface. The patterning is high-contrast against light sand and disappears completely against dark or mottled substrate, which is exactly what evolution intended.

In a store tank, expect to see a small group lined up motionless along the back glass with only the eyes and the top of the head exposed above sand. A startled horseface fires forward in a sudden burst, then re-buries within a second or two of stopping. Healthy specimens are alert to that approach response; lethargic individuals that fail to react are a warning sign.

Natural Habitat: Southeast Asian River Basins#

Wild Acantopsis dialuzona range across the Mekong, Chao Phraya, and Maeklong river basins of Thailand, Laos, Cambodia, Vietnam, and into the Malay Peninsula and Borneo. They occupy the slow-to-moderate flow zones along sandy banks and the soft margins of larger rivers, where fine sediment supports the kinds of small invertebrates and organic detritus they sift for food. The water is warm year-round (75-82F), neutral to slightly acidic, and soft to moderately hard depending on the basin.

The substrate is the defining feature of the habitat. These are not rocky-stream fish; they are river-margin sand specialists. Try to replicate that environment in the tank and the species reveals natural foraging behavior almost immediately.

Growth Expectations: Reaching 8+ Inches in Captivity#

Captive-raised horseface loaches typically reach 6 to 8 inches over 2 to 3 years, with well-fed individuals occasionally pushing past 9 inches. Wild specimens have been recorded slightly larger. Their slender, eel-influenced body plan makes them look smaller than they are when partially buried — what looks like a 4-inch fish in the tank often turns out to be a 7-inch fish with most of itself out of sight. Lifespan is genuinely long for a sand-sifter at this size: 8 to 10 years in stable conditions, which justifies setting up the tank correctly the first time.

Water Parameters & Tank Requirements#

The species is forgiving on water chemistry once acclimated, but it is unforgiving on substrate, lid security, and medication choice. Get the tank floor right and the rest is straightforward.

The Critical Need for Soft Sand Substrate (Burrowing Behavior)#

Horseface loaches burrow. Constantly. It is not a stress response or a disease — it is the central behavior the species evolved to perform. They drive their snouts into the substrate, push forward with the body, and surface several inches or feet away with sand and detritus filtering out through the gills. Repeat this behavior dozens of times a day over an 8-year lifespan, and the math on substrate choice becomes brutal.

Lay the sand at least 2 inches deep across the entire tank floor — deeper at the back if you want to plant rooted species. A "Substrate Safety Test" before adding fish: rub a generous pinch of the substrate firmly between your thumb and forefinger for 15 seconds. If you feel any sharp edges, hear grinding, or see your skin scraped pink, it is too coarse for a horseface loach. Soft, rounded grains that flow like dry flour are correct.

Flow and Oxygenation: Mimicking Riverine Environments#

The natural habitat is moderate-flow river margin, not the still backwater of a slow blackwater stream. Aim for filtration that turns the tank over 5 to 7 times per hour, with the output diffused enough that it does not blow holes in the substrate or pin the loaches in place. A canister filter with a spray bar is ideal; a baffled hang-on-back works for tanks under 75 gallons. Add a small powerhead pointed across (not into) the sand bed if the tank is over 4 feet long.

Oxygenation matters because warm water holds less dissolved oxygen and the loaches spend most of their time near the substrate where oxygen is lowest. Surface agitation from the filter return, plus an air stone running overnight, keeps oxygen levels comfortable and reduces the rapid gill movement that signals stress.

Ideal Parameters: 75-82F, pH 6.0-7.5, and Soft Water#

Target a temperature of 75-82F (24-28C). Hold pH in the 6.0-7.5 range and hardness at 4-12 dGH — soft to moderately hard water suits them, and the wider tolerance is one reason the species is forgiving despite its substrate fussiness. Ammonia and nitrite must read zero; nitrates under 20 ppm are the goal, which means weekly 25-30% water changes for a stocked tank. Avoid temperature swings greater than 4F in 24 hours; like most warm-water Asian loaches, they handle steady warmth far better than fluctuation.

A 55-gallon tank is the practical minimum for a group of three or four adults. The footprint matters more than the volume — they need horizontal swimming and burrowing area along the sand bed, not vertical height. A 75-gallon (48 by 18 inch footprint) is the sweet spot if you have the space, especially for a group of five or six fish that have room to spread out without crowding each other into the same buried spot.

Diet & Feeding#

Wild horseface loaches sift sand for tiny crustaceans, worms, insect larvae, and organic detritus. They lean carnivorous — protein from invertebrates makes up most of the wild diet, with detritus playing a smaller, opportunistic role. In captivity they accept prepared foods readily, but the food has to actually reach the substrate, and a busy mid-water community can starve them out if you do not target-feed.

Sifting for Micro-fauna: How They Feed#

Watch a horseface loach feed and the burrowing behavior makes sense. The fish drives its snout into the sand, scoops a mouthful, then expels the sand through the gill openings while retaining anything edible — tiny worms, microcrustaceans, insect larvae, and softened pellet fragments. A mature tank with a deep sand bed develops a low-density invertebrate population in the upper substrate layer that the loaches harvest continuously. This is partly why undersized or sterile tanks (bare-bottom quarantine setups, brand-new aquariums with sterilized sand) underperform for this species.

Best Foods: Bloodworms, Daphnia, and Sinking Pellets#

Build the diet around sinking, animal-protein-forward foods. Frozen bloodworms, blackworms, daphnia, brine shrimp, and tubifex are all eaten enthusiastically. Sinking shrimp pellets, Hikari Vibra Bites, sinking carnivore pellets, and bottom-feeder tablets cover the daily staple. Repashy Community Plus or Bottom Scratcher gel foods are excellent supplements — the gel sticks to driftwood or a feeding dish long enough for slow eaters to find it.

Avoid relying on flakes or any food designed for surface feeders. Horseface loaches will eventually find what falls to the bottom, but they cannot compete with tetras, barbs, and rasboras at the surface, and a diet of "whatever drifts down" leaves them undernourished over months. Algae wafers are accepted but should not be the centerpiece of the diet — these are not herbivores.

Nighttime Feeding Strategies for Shy Specimens#

Horseface loaches are crepuscular to nocturnal. They are most active in low light and after lights-out, and a heavy daytime feeding schedule often leaves food for tankmates and almost nothing for the loaches. Drop the main feeding 30 to 60 minutes after the tank lights go off. Use a dim red-spectrum night light or moonlight LED to observe — the red wavelength does not register as "daylight" to most fish and lets you confirm the loaches are actually eating.

For especially shy individuals, target-feed using a turkey baster or feeding tube to deliver sinking food directly above their burrowing spots. A small piece of slate or a feeding dish on the sand makes target-feeding easier and concentrates the food before tankmates arrive.

Tank Mates & Compatibility#

Horseface loaches are pacifists toward fish that are too large to swallow. They occupy the bottom of the tank, ignore mid-water and surface fish, and never nip or chase. The compatibility question is mostly about what other fish do to them — and what they might do to anything tiny enough to be sifted up with the sand.

Peaceful Giants: Why They Ignore Most Community Fish#

In a community tank, an 8-inch horseface loach simply does not engage with other fish. They glide along the substrate, bury themselves, and emerge to feed without triggering territorial responses from anything that lives more than a few inches above the sand. This makes them surprisingly easy to integrate into established peaceful communities, despite their size.

Ideal Partners: Rasboras, Gouramis, and Other Loaches#

Best companions are mid- and upper-water species that share the same warm, soft-to-moderate, well-oxygenated water. Harlequin rasboras, lambchop rasboras, scissortail rasboras, congo tetras, rummynose tetras, and danios all work beautifully — they occupy the open water column and ignore the loaches entirely. Pearl gouramis, three-spot gouramis, and honey gouramis make excellent peaceful centerpieces. Larger rainbowfish (boesemani, turquoise) suit bigger setups.

Among bottom dwellers, peaceful larger loaches that share the same warm-water, sand-substrate preferences pair well. The closely related dojo loach and weather loach — actually the same species under two trade names — handle similar conditions and similar group dynamics, though the dojo prefers cooler temperatures than horseface loaches tolerate long-term. The much smaller black kuhli loach shares the same Southeast Asian biotope and the same sand-substrate requirement, and a mixed group of horsefaces and kuhlis in a 75-gallon planted tank looks the part of an Indochinese river margin. Larger plecos (bristlenose, rubber lip) also coexist without issue.

Species to Avoid: Aggressive Cichlids and Nipping Barbs#

Skip aggressive cichlids — even smaller "community" cichlids like rams and apistos will harass horseface loaches off feeding spots and pick at exposed snouts. Larger New World cichlids (jack dempseys, oscars, severums) are outright incompatible. Avoid known fin-nippers like serpae tetras, tiger barbs, and rosy barbs — the long, exposed snout is a target for any species that nips. Skip dedicated shrimp tanks entirely.

For broader context on stocking a peaceful community around horseface loaches, see our freshwater fish guide, which covers compatibility profiles across the common community species.

Common Health Issues#

Horseface loaches are scaleless or have only minute, deeply embedded scales. This changes how you treat disease — almost every standard medication needs to be dosed conservatively, and a few common treatments are outright lethal.

Skin Infections and Abrasions from Rough Substrate#

The most common health issue is preventable: sand abrasions and secondary bacterial infection from inappropriate substrate. Symptoms include red or pink patches along the snout and belly, eroded barbels, frayed fin edges, and a loach that spends increasing time hiding instead of burrowing. There is no medication that fixes this — the fix is to remove the rough substrate, replace it with appropriate fine sand, and let the fish heal in clean water. A round of broad-spectrum antibiotics (Furan-2 or Kanaplex) at half-dose can clear active secondary infections, but the substrate must be corrected first or the cycle repeats.

Sensitivity to Medications (Scaleless Fish Precautions)#

Ich (Ichthyophthirius multifiliis), gill flukes, and skin flukes are the most common parasitic problems. For ich, raise the temperature to 86F over 48 hours and hold for 10-14 days — heat alone clears most outbreaks without medication, which is the safest first option for a scaleless species.

"Skinny Disease" and Internal Parasites in Wild-Caught Stock#

Most horseface loaches in the trade are wild-collected, and a significant percentage arrive carrying internal parasites (camallanus worms, nematodes, capillaria). The classic symptom is "skinny disease": a loach that eats normally but loses condition over weeks, showing a sunken belly, visible spine, and progressive lethargy. Treat with levamisole (Expel-P) or fenbendazole (Panacur) following package directions for sensitive species, and dose the whole tank rather than just the symptomatic fish. A 4-week prophylactic deworming during quarantine is a defensible practice for any wild-caught loach.

Where to Buy & What to Look For#

Horseface loaches are usually wild-collected and travel poorly compared to tank-bred species. They lose mucus, abrade easily in bags, and arrive stressed. Buying from a knowledgeable local fish store almost always beats ordering online for this species.

Inspecting the Snout for Shipping Damage#

When inspecting horseface loaches at the store, focus on the snout. The downward-sloping nose and the barbels around the mouth are the first thing to suffer in shipping — pressed against bag walls or rubbed raw on rough store substrate, the snout shows damage as red patches, frayed skin, or visibly shortened barbels. Skip any individual with a visibly chewed-up snout, even if the rest of the body looks healthy. The injury heals slowly and predisposes the fish to infection during the stress of moving to a new tank.

The body should be uniformly tan-gold along the back, with crisp dark blotches along the lateral line. Avoid loaches with a washed-out, gray cast (a stress and dehydration sign), red or pink patches anywhere on the belly, frayed fins, or rapid gill movement. A healthy horseface in a store tank is alert: it tracks your approach with its eyes and either holds position confidently or fires forward in a brief startle response. A fish that does not react to a hand near the glass is a fish in trouble.

Ask the staff how long the fish have been in-store. Two to three weeks is the sweet spot — long enough to clear shipping stress and start eating, short enough that the staff can verify they are healthy and feeding. Watch a feeding if you can. Healthy horsefaces emerge from sand for sinking food within five to ten minutes once it hits the substrate.

Why Quarantining Wild-Caught Loaches is Mandatory#

Quarantine every horseface loach for a minimum of 4 weeks before adding to the display tank. A simple quarantine setup is a 20-gallon long with fine sand (yes, even in QT — burrowing loaches stress without it), a sponge filter, a heater, and a few PVC sections for cover. During quarantine, run a prophylactic deworming with levamisole, observe for ich and external parasites, and make sure the fish is eating prepared foods reliably.

For broader context on the kind of warm, well-filtered, sand-substrate environment horseface loaches need, see our freshwater fish guide, which covers the foundational setup decisions for community planted tanks. If you are new to acclimation, our acclimation guide walks through the drip method that works best for sensitive wild-caught loaches.

Quick Reference#

• Tank size: 55 gallons minimum (75+ gallons preferred for groups of 5+)
• Temperature: 75-82F (24-28C)
• pH: 6.0-7.5 (soft to moderately hard)
• Hardness: 4-12 dGH
• Substrate: Fine sand only — pool filter sand or play sand under 1 mm grain size; never gravel
• Group size: Minimum 3, ideally 5+
• Diet: Sinking carnivore pellets, frozen bloodworms, daphnia, blackworms; feed after lights-out
• Tankmates: Rasboras, larger tetras, gouramis, peaceful loaches, plecos
• Avoid: Aggressive cichlids, fin-nippers, dwarf shrimp tanks, fry-rearing setups, copper meds at full dose, aquarium salt
• Lid: Tight-fitting — horseface loaches can jump and squeeze through small gaps
• Lifespan: 8-10 years
• Difficulty: Intermediate (substrate-fussy, scaleless medication sensitivity)