Horseface Loach

The Horseface Loach has a long nose and loves to rummage through the substrate for morsels of food!

The Horseface Loach Acantopsis choirorhynchos is and interesting aquarium inhabitants that enjoys burrowing. It is also known as the Horsehead Loach and its overall shape is quite suited to its habits. It likes to burrow into the substrate and will sift the sand through its gills in search of microorganisms or other food.

The body of the Horseface Loach is elongated, with a flat belly. The snout is characteristically long and bends downward about halfway between the eyes and nose. It strongly resembles a horse! (go figure) The eyes are covered with a transparent layer and are perched near the top of the head, and slightly protrude from the head. There are no scales on this fish’s head. The back and sides of the fish are light brown with various spots and stripes. The lower parts of the fish are white while the fins are brownish.

Be careful when purchasing as they are sometimes offered for sale as a “Long-nosed Loach” and vice-versa. The Long-nosed Loach is actually a different species, Acantopsis octoactinotos. The two species resemble each other but the Long-nosed Loach is more aggressive (will eat smaller fish like Neon Tetras and Zebra Danios) and is not a burrower. The Long-nosed Loach also does not have the characteristic downturn on its snout.

They have a quiet disposition and make a great community fish.They are generally quite peaceful but they will defend a territory against members of their own species. It is best to keep single fish with other community fish. They enjoy burrowing and should be provided a rounded sand or fine gravel substrate. Provided with the right habitat and a properly maintained aquarium and these hardy fish will reward the aquarist with an interesting and long lived pet.

• For information on keeping freshwater fish, see: Freshwater Aquarium Guide: Aquarium Setup and Care

Habitat: Distribution / Background

The Horseface Loach Acantopsis choirorhynchos was described by Bleeker in 1854. It is found in Southeast Asia; Borneo, Burma (Myanmar), Java, Malaysia, Sumatra, Thailand, and Vietnam. They are also known as the Horsehead Loach. This species is listed on the IUCN Red List as Least Concern (LC). However these Loaches have not been studied very well. Their apparently large distribution, extending across the majority of Indochina and beyond, may indicate that this species actually represents a cluster of yet undescribed, but very similar species. Another common name this fish is known by is Horsehead Loach.

They inhabit rapid streams with a sandy or rocky substrate as well as large, slow moving rivers with substrates of sand, fine gravel or mud. During monsoon season they will temporarily migrate into the flooded areas of the region. They will burrow into soft substrates and sift mouthfuls through their gills to extract insect larvae, small crustaceans, and other benthic organisms.

• Scientific Name: Acantopsis choirorhynchos
• Social Grouping: Groups
• IUCN Red List: LC – Least Concern

Description

The Horseface Loach is a good sized fish that can get up to 8 inches (20 cm) or more in the wild, though they are usually smaller in the aquarium. They generally have a life span of about 10 – 12 years.

The body of this interesting loach is elongated, with a flat belly. The snout is characteristically long and bends downward about halfway between the eyes and nose. It strongly resembles a horse! (go figure) The eyes are covered with a transparent layer and are perched near the top of the head, and slightly protrude from the head. There are no scales on this fish’s head. The back and sides of the fish are light brown with various spots and stripes. The lower parts of the fish are white while the fins are brownish.

• Size of fish – inches: 11.8 inches (30.00 cm) – These fish are can reach between 8 – 11 3/4 inches (20 – 30 cm) in the wild, but are usually smaller in the aquarium.
• Lifespan: 12 years – Their lifespan is generally about 10 – 12 years.

Fish Keeping Difficulty

This loach can be hardy under the right conditions. They are not recommended for beginners because of their need for pristine water and having small body scales and no scales on the head. Reduced scales makes them more prone to disease and very sensitive to medications used to treat disease. Experience in treating scaleless fish is very important to be able to give your loach a healthy and long life. Do not try to introduce these fish into biologically immature tanks.

• Aquarium Hardiness: Moderately hardy
• Aquarist Experience Level: Intermediate

Foods and Feeding

Since they are omnivorous, the Horseface Loach is not a picky eater. In nature this loach feeds primarily on insect larvae, small crustaceans, and other benthic organisms. But in the aquarium it will generally eat all kinds of live foods, sinking pelleted and tablet foods, flakes, and algae. They like frozen foods as well. To keep a good balance give them a high quality flake or tablet food everyday. Feed mosquito larvae and brine shrimp (either live or frozen), tubifex, daphnia, and some vegetable foods such as algae wafers.

• Diet Type: Omnivore
• Flake Food: Yes
• Tablet / Pellet: Yes
• Live foods (fishes, shrimps, worms): Some of Diet
• Vegetable Food: Some of Diet
• Meaty Food: Most of Diet
• Feeding Frequency: Several feedings per day

Aquarium Care

The most important thing for these loaches is that they always have clean and well-oxygenated water. Frequent water changes of 30 – 50% a week are needed. With your weekly water change make sure to vacuum the gravel to remove all excess food and waste. Make sure not to remove the bio film on rocks, decor or no viewing panes of the tank. A magnet algae cleaner normally does a great job in keeping the viewing pane clear.

• Water Changes: Weekly – Water changes of 30 – 50% weekly.

Aquarium Setup

These loaches will swim mostly on the bottom of the aquarium, but will occasionally swim in the middle or upper parts of the aquarium. Smaller Horseface Loaches do fine in a medium sized aquarium (20 gallons or so), but a full grown loach, up to 8 inches, needs a larger 35-45 gallon aquarium. A group will need even more room starting at 55 gallons and up.

Never introduce this loach into a biological immature setup as these fish require pristine water. They do best in soft, slightly acidic water and also use subdued lighting. They need good water movement that provides plenty of oxygenation. Using an over sized external power filter will help meet that requirement. Powerheads and River manifolds can be used to create the proper current for these loaches. This is one of the loaches that can also be acclimated to a low-salinity brackish water aquarium. Keep specific gravity less than 1.005 and preferably less than 1.003.

Because they are burrowers, the substrate needs to be a fine gravel or sand that does not have sharp edges. There should be lots of plants and places for retreat such as rocks, caves, and roots. Be sure to provide hardy plants with the roots protected and have decorations firmly placed on the glass bottom so they don’t fall over. Plastic tubes also make safe and excellent hiding places.

• Minimum Tank Size: 55 gal (208 L) – Juveniles will be fine in 20 gallons or more but a full grown adult needs 35 – 45 gallons minimum, with 55 gallons or more needed for a group.
• Suitable for Nano Tank: No
• Substrate Type: Sand/Gravel Mix – Should be soft enough so they can burrow without injury.
• Lighting Needs: Low – subdued lighting
• Temperature: 79.0 to 84.0° F (26.1 to 28.9&deg C)
• Range ph: 6.0-7.0
• Hardness Range: 1 – 10 dGH
• Brackish: Sometimes – This is primarily a freshwater fish but it can be acclimated to low-salinity brackish water conditions. Keep specific gravity less than 1.005 and preferably less than 1.003.
• Water Movement: Moderate
• Water Region: Bottom – These fish are mostly bottom dwellers, but will occasionally swim in the middle or upper parts of the aquarium.

Social Behaviors

A nocturnal fish, the Horseface Loach will usually hide during the day, but are lively and active in the evening. These loaches are a good community fish, especially with peaceful but active top and mid-dwelling tankmates.

They are loosely aggressive towards members of their own species, so it’s best to keep one per aquarium unless there is lots of space and caves for each to stake out its own territory. These loaches form a social hierarchy and should be kept in groups of ideally 6 or more, with a minimum of three. Be prepared for the occasional fight over territory, which normally do not end in injury.

• Venomous: No
• Temperament: Peaceful
• Compatible with:
  • Same species – conspecifics: Yes – A group of 6 or more is best, with a minimum of three.
  • Peaceful fish (): Safe – This loach is compatible with top and mid-dwelling active fishes.
  • Semi-Aggressive (): Monitor
  • Aggressive (): Threat
  • Large Semi-Aggressive (): Threat
  • Large Aggressive, Predatory (): Threat
  • Monitor
  • Shrimps, Crabs, Snails: May be aggressive
  • Plants: Monitor

Sexual differences

Full-grown females will probably have a rounder abdomen. In most cases females grow considerably larger than males.

Breeding / Reproduction

Not much is known about the breeding habits of the Horseface or Horsehead Loach and they are not yet bred commercially.

• Ease of Breeding: Unknown

Fish Diseases

Loaches are more susceptible to disease than other aquarium fishes. This may have to do with the faint body scales and no head scales. So take caution when introducing the Black-Lined Loach to an established tank. They are also very sensitive to different medications used to treat many diseases; a separate hospital tank is needed. Cold water and condition changes can also cause stress to this fish which makes them even more prone to disease.

Most common disease that affects this loach is Ich. Ich is short for Ichthyophthirius, also known as “white spot disease”. It is a parasite that can attack nearly all aquarium fishes, but you’ll find that loaches are often the first to be attacked. Take great care in treating ick as loaches are very sensitive to the medications used to treat it. Often the dose is half of what is normally used.

The second most common thing that affects loaches is a thing called skinny disease. This can be diagnosed fairly easily. If your loaches are eating a nitrous and healthy amount and still seems to loose weight it is a good chance it has skinny disease. This is caused by internal parasites and can be treated with medication if used carefully.

An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping these sensitive types of fish, it is common to catch deteriorating water conditions and disease before other fish are affected. The best way to proactively prevent disease is to give your Horseface Loach the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease.

Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.

Availability

The Horseface Loach or Horsehead Loach is usually available. Be careful when purchasing however, as they are sometimes offered for sale as a “Long-nosed Loach” and vice-versa. The Long-nosed Loach is actually a different species, Acantopsis octoactinotos. A. octoactinotosis is a more aggressive species and can be predatory with smaller Neons, Danios, and Tetras.

 Acantopsis choirorhynchos (Image Credit: Alter welt, Wikimedia Commons CC BY-SA 4.0 International)