Order Cypriniformes ( Cypriniformes )
Family Cobitidae ( Cobitidae )
Subfamily Cobitinae ( Cobitinae )
Genus Acantopsis — Acantopsis.
Basically, only Acantopsis choirorhynchus and Acantopsis octoactinotos are available for purchase; they are very similar to each other, and at a young age, it is practically impossible to tell them apart. Other species also share an appearance and behavior common to all Acantopsis, but finding them for sale is even harder.
— Horsefaced Loach, Horsehead Loach — Acantopsis choirorhynchos [Bleeker, 1854]. Synonym: Acanthopsis choerorhynchus, choirorhynchus, dialuzona, Cobitis choirorhynchos. (English: Horsefaced Loach, Horsehead Loach, Banana Loach, Long Nosed Loach). Myanmar, Thailand, Vietnam, Malaysia, Indonesia, Sumatra, Java, Borneo. Streams and shallow rivers with a slow current. 28 cm, in an aquarium up to 12-15 cm, but growing slowly.
The beige-gray coloration is interrupted by two longitudinal rows of coffee-colored spots located at equal distances from each other along the midline. There are dark specks on the head, dorsal, and caudal fins. The belly is white, and the fins are brownish. In the male, the pectoral fins are larger, the first ray is strongly developed, and the pattern is clearer. Females are larger, plumper, and have a more reddish color, whereas males are more silvery-gray.
Keeping them requires a relatively large aquarium with a volume of 150 liters for a pair of fish. The aquarium should be densely planted with vegetation, including floating plants, and have a large number of shelters in the form of driftwood, stones, and grottoes. It is very important to choose tank mates correctly: Acantopsis do not like the company of overly large, aggressive, or too active fish, especially inhabitants of the lower water layers — in this case, they will spend even more time burrowing in the substrate, making them practically impossible to see.
The fish lead a predominantly solitary lifestyle and do not have a great need for the company of their own kind, so even a single Acantopsis will feel quite comfortable in an aquarium. It is preferable to keep them with any peaceful fish inhabiting the middle and upper layers, as well as with small catfishes and loaches. You should also know that due to their timidity, you need to choose smaller and non-aggressive tank mates for these fish; otherwise, Acantopsis will constantly hide by burrowing into the substrate, making it practically impossible to observe them.
Very secretive and timid, leading a nocturnal lifestyle, they are rarely seen in the aquarium because they spend most of their time in hiding or completely buried in the substrate, coming out only after dark. They love to burrow into the sand so that only their eyes remain visible. You should only get these fish if they are of interest in themselves and the owner is ready to provide them with proper maintenance conditions; otherwise, a person who buys them as ordinary aquarium fish for decorative and aesthetic purposes will likely be greatly disappointed.
They dig strongly in the substrate, undermining loosely rooted or small plants. To prevent this, it is advisable to plant vegetation in pots. Their digging can disrupt decorative rocks, plants, and shelters. Sand or fine gravel with a particle size of 1-2 mm without sharp edges is mandatory as a substrate, with a layer of at least 3-4 cm for young fish, and at least 5-7 cm for adults, because without the ability to burrow completely, the fish will experience constant stress and begin to suffer from skin diseases with age.
They fear bright light and therefore cannot tolerate direct illumination; it is recommended to cover the water surface with floating plants. The more cozy and calm the atmosphere in the aquarium, the more time the fish will spend on the surface of the substrate, but seeing them crawling in daylight is in any case a very rare stroke of luck. If you have trouble observing the fish, you can turn on a small green or blue LED backlight after turning off the main lighting.
The water should be soft (not exceeding 10° dH), and the temperature should not exceed 26°C. Good filtration and aeration, regular thorough gravel vacuuming, and weekly water changes are mandatory. Care must be taken during gravel vacuuming — the fish bury themselves completely, and if the sand layer is quite thick, it is not always possible to determine where exactly they are buried. Live and frozen foods that sink to the bottom are suitable as food. Acantopsis do not breed in aquarium conditions. The lifespan of the fish is about 5 years. dH 5-15°; pH 6.0-7.5; T 23-26°C.
Identification: Horsefaced Loach — Acantopsis choirorhynchos.
— Eight-rayed Horseface Loach — Acantopsis octoactinotos [Siebert, 1991]. (English: Long Nosed Loach). Myanmar, Thailand, Vietnam, Malaysia, Indonesia. Streams and shallow rivers with a slow current. 10-12 cm. Light body background, slightly mottled with black or dark gray spots, ideal for camouflage in an aquarium with a sandy bottom. The female is larger and more massive.
Often confused with A. choirorhynchos; at a young age, it is practically impossible to tell them apart. The differences are: • A. choirorhynchos has a more curved snout. It is less aggressive. Spends most of its time buried in the substrate; • A. octoactinotos has a straighter and slightly shorter snout. Does not burrow into the substrate. Slightly smaller in size. Usually rests on rocks or plants.
They lead a nocturnal, solitary lifestyle and are rarely seen in the aquarium. They are very timid and constantly hide in shelters or burrow into the substrate, spending the entire daylight period that way. It is very important to choose tank mates correctly: Acantopsis do not like the company of overly large, aggressive, or too active fish, especially inhabitants of the lower water layers. It is preferable to keep them with any peaceful fish inhabiting the middle and upper layers, as well as with small catfishes and loaches. These fish feel quite comfortable alone, but they also behave absolutely peacefully among themselves.
The aquarium should be densely planted with vegetation, including floating plants, and have a large number of shelters in the form of driftwood and stones. They do not like open spaces and bright light, and feel good in aquariums decorated with driftwood, stone caves, and sufficient plant thickets. Lighting should be diffused, of low intensity. The substrate should be soft, sandy, about 7 cm thick; without the ability to burrow completely into the substrate, the fish will experience constant stress and begin to suffer from skin diseases with age. It is very important that the substrate is not sharp to avoid injuring the fish when they dig in it.
Due to their ability to burrow into the substrate, they very often uproot plants along with their roots. Plants should be planted in pots with gravel for ballast, and floating plants used to reduce illumination. Good aeration, regular thorough gravel vacuuming, and water changes are mandatory. Any suitable-sized live or frozen food sinking to the bottom is fine; they get used to bottom-feeder tablets.
It is better to feed in the evening after turning off the light in the aquarium — fish may come out to feed during the day in bright light only in case of extreme hunger, but they should not be brought to such a state. Care must be taken during gravel vacuuming — the fish bury themselves completely, and if the sand layer is quite thick, it is not always possible to determine where exactly they are buried. Acantopsis do not breed in aquarium conditions. Lifespan is about 5 years. pH 5.5-6.5; dH 5-15°; T 25-28°C.
Misgurnus anguillicaudatus, Misgurnus fossilis.
Genus Cobitis, Genus Lepidocephalichthys, Genus Serpenticobitis. 
