The Zipper Loach has a beautiful patterning when it is young that looks just like a zipper!

The Zipper Loach Acanthocobitis botia is a beautiful, slender, elongated fish with a decorative pattern, especially as a juvenile. It is also a nice sized river loach reaching between 3 to 4 1/3 inches (10 – 12 cm) in length, though generally staying on the smaller size in the aquarium. It has a grayish green background color with a lighter, whitish belly and dark blotches on the sides and top. The dorsal and tail fin have stripes made up of dark spots. If well cared for it can also have an orange-red cast to its fins.

The most common name for this loach is Zipper Loach, but is described by many other common names, most of which are indicative of its looks. When it is young as it looks like it is covered with a ‘zipper’ pattern. It also has a unique ‘eye-spot’ on the top part at the base of the caudal fin, lending to the name Eye-Spot Loach or Spot Loach. But as this loach grows its pattern stretches out and other distinctive names come into play, such as Mottled Loach or Striped Loach. The only odd-ball name is Sand Loach, which probably comes from its preference for digging and hiding in soft substrates such as sand or fine gravel.

The Zipper Loach is nocturnal and can be quite shy until it becomes acclimated. Provide subdued lighting and be sure to provide plenty of hiding and resting places created with rocks and driftwood. As they like to burrow, a substrate of sand or fine gravel is best. Plants are not necessary but they are appreciated.

Zipper Loaches are hardy, personable, and generally peaceful. They are good for a community aquarium, but with reasonably robust tank mates. They have been known to nip angelfish and gouramis who have longer fins. Though most Hillstream loaches are best kept singly as they have a tendency to quarrel with others of their own species, this one has reportedly been kept with others of its own kind.

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

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Cypriniformes
  • Family: Balitoridae
  • Genus: Acanthocobitis
  • Species: botia
Zipper Loach – Quick Aquarium Care
  • Aquarist Experience Level: Intermediate
  • Size of fish – inches: 4.3 inches (11.00 cm)
  • Minimum Tank Size: 30 gal (114 L)
  • Temperament: Semi-aggressive
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
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Habitat: Distribution / Background

The Zipper Loach Acanthocobitis botia (Syn: Noemacheilus Botia) was described by Hamilton in 1822. It is found in Asia; especially India, Thailand, and China. Other common names they are known by include Mottled Loach, Eye-Spot Loach, Spot Loach, Sand Loach, and Striped Loach.

There are different colorations and body patterning with this species depending on the region where the loach resides. These numerous geographical forms have created some confusion. Although some have been described as distinct species over the years, all are considered at this time to represent a single species described as A. botia. Most of the Zipper Loaches seen in the trade appear to originate from India.

The A. botia is listed on the IUCN Red LIst as Least Concern (LC). It has been assessed as least concern because, although there are reports of a large decline in some habitats in Pakistan, but it is not thought to be a significant affect on a global scale.

These loaches are found in many river drainages of the Ganges, Ayeyarwady and Salween. These loaches live in a variety of conditions and some have very seasonal changes, such as swelling waters during monsoon seasons and very low waters during the drier seasons. They do seem to gravitate towards areas of rivers and streams that have leaf and debris collected with areas of open sand and boulders. Many of their habitats are void of any aquatic plants. In nature these loaches are micropredators and will feed on insects, larvae, and plant matter.

  • Scientific Name: Acanthocobitis botia
  • Social Grouping: Groups – Lives in loose groups.
  • IUCN Red List: LC – Least Concern


The Zipper Loach has a slender, elongated body. It can reach up to 4 1/3 inches (11 cm) in the wild, though it is usually smaller in the aquarium, and has a life span of 8 years. It has a grayish green background color with a lighter, whitish belly and dark blotches on the sides and top. The dorsal and tail fin have stripes made up of dark spots. If well cared for it can also have an orange-red cast to its fins.

When it is young this loach looks like it is covered with a ‘zipper’ pattern, hence the common name Zipper Loach. It also has a unique ‘eye-spot’ on the top part at the base of the caudal fin. As this loach grows, the zipper pattern stretches out and becomes more of a mottled or striped pattern.

  • Size of fish – inches: 4.3 inches (11.00 cm) – These fish can reach between 3 – 4 1/3 nches (8 – 11 cm) in the wild, but are usually on the smaller side in the aquarium.
  • Lifespan: 8 years

Fish Keeping Difficulty

The Mottled Loach is suggested for a more experienced aquarist because of their need for pristine water and their lack of scales. Not having scales make 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.

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

Foods and Feeding

The Zipper Loach are omnivores that feed on insects, larvae, and plant matter in the wild. It also gets some of its nutrients from sifting sand through its gills. In this manner it can remove microscopic foods from the substrate.

In the aquarium they 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, 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

For this loach to thrive it is important that the water be clean and well-oxygenated. Weekly water changes of at least 30% are needed to keep the loach healthy. With your weekly water change make sure to vacuum the gravel to remove all excess food and waste. Make sure not to remove the biofilm from the rocks, decor, or glass other than the 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 at least 30% weekly.

Aquarium Setup

These fish are mostly bottom dwellers. Because the Mottled Loaches do best in groups, a larger tank will work best, at least 30 gallons. The tank needs to have ample hiding places for this shy fish to retreat such as rocks, caves, and roots. They do best in soft, slightly acidic water.

It is recommended to have a tank set-up that resembles its natural habitat, moving rivers. The substrate should be sandy or small smooth gravel. This is very important because this loach will sift sand through its gills to remove microscopic foods from it. Larger smooth rocks should be used as hiding places. Driftwood and branches should be added to provide shade and places for quick retreat. Java Ferns can be introduced and will attach to the decor. Powerheads or a rivertank manifold can be added to provide a unidirectional flow to simulate its natural habitat. Be sure to have ample smooth surfaces to encourage biofilm to grow.

The most important thing for these loaches is that they always have clean and well-oxygenated water. An over sized filter will meet that requirement. The tank water turnover should be at least 10-15 times per hour. A high quality canister filter works great and will clean as well as help create water movement. Powerheads and airstones can also be introduced to help achieve proper flow and oxygenation.

  • Minimum Tank Size: 30 gal (114 L)
  • Suitable for Nano Tank: No
  • Substrate Type: Sand – Subtrate must be very fine. This loach will sift the sand through its gill for nutrients.
  • Lighting Needs: Moderate – normal lighting
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
  • Range ph: 6.6-7.8
  • Hardness Range: 2 – 8 dGH
  • Brackish: No
  • Water Movement: Strong
  • Water Region: All

Social Behaviors

The Zipper Loach is best kept with fish that are robust or else tank mates might be bullied. On the other hand, if not provided some shelter, the Zipper Loach may be shy and reclusive. They are peaceful in a community aquarium with mildly aggressive tank mates, but have been know to nip fish with longer fins such as angelfish and gouramis.

Though they hide during the day, they can be lively and active in the evening or when feeding. They seem to do best with fish from its native habitats. Great choices are Puntius, Danio and Laubuca. Other peaceful loaches will do well also. Avoid aggressive nemacheilids and Schistura.

Most Hillstream loaches are best kept singly as they have a tendency to quarrel with others of their own species and other similar loaches. However the Zipper Loach can be kept with others of its own kind. In nature these loaches live in loose aggregations and should be kept in groups of 6 or more to see their true personalities.

  • Venomous: No
  • Temperament: Semi-aggressive –
  • Compatible with:
    • Same species – conspecifics: Yes – Although most aquarists suggest keeping Hillstream Loaches singly, this fish seems to do fine as long as the group is big enough to diffuse aggression.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Threat
    • Shrimps, Crabs, Snails: Safe – not aggressive
    • Plants: Safe

Sex: Sexual differences

The males are thinner and has a definite groove under the eyewhich the females do not.

Breeding / Reproduction

There are reports of the Zipper Loach having spawned for hobbyists but not much is known about their breeding habits. They are not yet bred commercially.

  • Ease of Breeding: Unknown – Spawnings in the home aquarium are rare and mostly accidental.

Fish Diseases

The Zipper Loaches are scaleless and prone to disease, so take caution when introducing these fish to an established tank. The Mottled Loach is also very sensitive to medication 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.

Loaches are more susceptible to disease than other aquarium fishes, which may have to do with the faint body scales and no head scales. The most common disease that this loach is susceptible to 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 something called skinny disease. This can be diagnosed fairly easily. If your loaches are eating a nutritious diet and in healthy amounts, and still seem to be loosing weight, there is a good chance they have skinny disease. This disease 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 Eye-Spot 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 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.


The Zipper Loach is generally available.