Home / Fishes / Carp, barbs, minnows, loaches / Cobitidae / Horse-faced Loach

No federal permit to keep

Horse-faced Loach

Acantopsis dialuzona

Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Cobitidae (Spined loaches)

Acantopsis dialuzona is a loach native to the swift, clear streams and rivers of mainland and archipelagic Southeast Asia, Indonesia, Peninsular Malaysia, Thailand, but Southeast Asia outside its range, including as Acantopsis.

Aquarium hobby

Experience: Easy

FamilySpined loaches

Adult lengthup to 9.8 in

WaterFreshwater

HabitatLives in freshwater

Care at a glance

Species-specific aquarium care

Tank: At least 42 in long and 21 in front to back for one adult (adults commonly reach about 9.8 in / 25 cm).
Water: Freshwater.
Temperature: 77–82°F (range recorded for this species).
pH: 6–6.5.
Hardness: 0–10 dGH.
Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.

Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.

Care guide

Species care notes

Tank: a base of at least 47 × 18 in (roughly 64 US gallons); space needed is rated “large tank”.
Water: a fairly wide range, from slightly acidic to slightly alkaline, 61–75 °F, pH 6–8, 1–12 dGH.
Behaviour: a shoaling fish best kept in a group of six or more; suited to a community tank.
Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

Setup: “Not difficult to keep but must be provided with a soft, sandy substrate since some of its time will be spent completely buried, or with only eyes protruding.”
Tankmates: “In a set-up as described above these loaches will do well alongside species that inhabit the upper part of the water column such as Rasbora, Devario, Laubuca and Barilius spp.”

From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167

Group care guide

Spined loaches

Applies to most species in this group. Habitat: Spined loaches inhabit freshwater bottoms from tropical Pangio forest streams and swamps to temperate weather-loach streams, wetlands and paddy fields. Individual species can differ, so compare with the species numbers above and the linked sources.

The water range is for tropical P. semicincta; weather loaches require about 64–74°F for general care and should not be maintained as tropical fish indefinitely. Do not transfer these settings automatically to Cobitis paludica, taenia or sinensis, or Acantopsis dialuzona: verify species-specific care. Fish sold as P. kuhlii are often P. semicincta or relatives. Weather loaches are invasive outside their native range; the cited profile recommends indoor containment rather than outdoor maintenance. Level 2 describes the common Pangio/weather-loach pathway, not every cobitid.

Housing & setup

For Pangio semicincta, provide at least a 60 × 30 cm (24 × 12 in) footprint; adult Misgurnus anguillicaudatus need at least 120 × 45 cm (48 × 18 in).
Use soft sand for burrowing; coarse gravel can injure fish and inhibit feeding.
Provide shaded retreats beneath secured wood or smooth rocks, with leaf litter and low-light plants for Pangio.
Cover the aquarium securely and protect filter intakes against entry by small loaches.
Use mature biological filtration, gentle circulation and surface agitation rather than strong flow for Pangio and weather loaches.

Sources 892 893 894

Climate & lighting

Water

70–79°F

Sources 892 893 894

Diet

Sinking complete foods reaching the bottom.
Live or frozen Daphnia and Artemia.
Bloodworms and small worms as part of a varied diet.

Sources 892 893 894

Social life

Keep Pangio in groups of at least five or six with peaceful companions. Weather loaches can be kept singly but appear more active with conspecifics; they may eat eggs, fry or tiny fish.

Sources 892 893 894

Health watch

Skin injuries and feeding impairment from unsuitable burrowing substrate.
Ammonia-related illness in immature aquaria.
Nutritional deficiencies if bottom dwellers receive insufficient suitable food.

Sources 892 893 894

Understanding the animal

About this animal

A. choirorhynchos because of the lack of taxonomic resolution in Acantopsis. It can also be found in flooded fields.

Quoted from the Wikipedia article “Acantopsis dialuzona” (CC BY-SA 4.0) 174

In the wild

From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.¹

Where it lives	Lives in freshwater, in rivers and streams. Stays near the bottom. Inhabits rivers where they feed on small animals in the bottom sediments. Occurs in swift, clear streams with sandy or gravelly bottom; also found in large rivers.
Water it lives in	Freshwater, 77–82 °F (25–28 °C), pH 6–6.5, hardness 10 dH.
Climate	Tropical climate.
Wild diet	Hunting macrofauna (predator).

What this means for care

Keep water within its wild range, 77–82 °F.

FishBase species summary: Acantopsis dialuzona

Native climate (measured)

Warm-season highs	about 91°F (up to 98°F in the hottest sampled areas)
Cool-season lows	about 69°F (down to 55°F in the coldest sampled areas)
Average temperature	77–82°F across sampled records
Relative humidity	72–80% on average (driest month about 68%)
Rainfall	about 1950 mm a year, with strong wet and dry seasons

Measured at 78 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

Overview	Acantopsis dialuzona is a loach native to the swift, clear streams and rivers of mainland and archipelagic Southeast Asia, Indonesia, Peninsular Malaysia, Thailand, but Southeast Asia outside its range, including as Acantopsis. A. choirorhynchos because of the lack of taxonomic resolution in Acantopsis. It can also be found in flooded fields. The horseface loach or horsehead loach, formerly known as Acantopsis choirorhynchos, is now recognized as belonging to this species. — Wikipedia (community-edited)
Where it lives	Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase
Biology	Inhabits rivers where they feed on small animals in the bottom sediments. Occurs in swift, clear streams with sandy or gravelly bottom; also found in large rivers. — FishBase
History and naming	Under Maurice Kottelat's review and revision of the loaches in 2012, this species name is considered to be a junior synonym of A. dialuzona. — Wikipedia (community-edited)

Data and studies

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Typical adult weight

Reported50g

FishBase 16450

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Adult length

Average of sources8.9in

FishBase 1649.8

Seriously Fish species profiles 1677.9

Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.

Water temperature

Average of sources69–78.5°F

FishBase 16477–82

Seriously Fish species profiles 16761–75

Range the species tolerates in nature; aim for the middle.

pH

Average of sources6–7.2

FishBase 1646–6.5

Seriously Fish species profiles 1676–8

Water hardness

Reported1–12dGH

Seriously Fish species profiles 1671–12

Minimum tank footprint

Reported47in

Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 18 in (about 64 US gallons).

Federal legal snapshot

No federal permit to keep

No federal law singles out this species for private keepers. State and local rules still apply.

State law decides most of it. Each state sets its own permits and bans for exotic, native, venomous and dangerous animals, and cities and counties can be stricter. Find your state agency →

Not covered by the Animal Welfare Act

The Act only covers warm-blooded animals. Reptiles, amphibians, fish and invertebrates have no federal care standards, even at licensed facilities; state and local rules may still apply.

Kept in captivity?

Every species on this site needs evidence that people actually keep it. For this one:

FishBase records it in the aquarium trade (Aquarium=commercial; AquariumFishII=based mainly on breeding)
11 iNaturalist observations of captive animals
Has a Seriously Fish aquarium species profile

Sources for this sheet

FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
Seriously Fish — pangio semicincta Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
Seriously Fish — misgurnus anguillicaudatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
Merck Veterinary Manual — Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.