The wiggly little Kuhli Loach keeps quite busy snacking on foods left uneaten by the other fish!

The Kuhli Loach Pangio kuhlii is an active, fascinating little fish. Its behaviors are typical of all members of the Pangio genus. It keeps in almost constant motion, actively scurrying around, over, and through the plants and ornamentation. It is scavenging for leftover foods that have settled on the bottom of the aquarium. This is a great little helper in keeping the aquarium clean and in good shape..

This little fish was originally named and is best known as the Kuhli Loach or Prickly Eye, but there are quite a few other common names often associated with this fish. For example, in the United States this loach is sometimes also called the Coolie Loach, Giant Coolie Loach, Leopard Loach, and Cinnamon Loach. Coolie Loaches are exported by the millions for the aquarium hobby.

Though peaceful, the Kuhli Loach is nocturnal and is most active at night. They can also be quite shy and will seldom be seen if kept alone. This doesn’t mean they are a schooling fish, as they are not, but they are more comfortable and more likely to come out of hiding if they have some companions. A group of a half dozen or so will make them more prone to behave as they would in nature. They are quite hardy and can live for several years.

The term ‘kuhli loach’ is often used collectively to refer to a group fish in the Pangio genus (previously the Acanthophthalmus genus) that are much like the actual Kuhli Loach. These loaches all have the elongated wormlike body shape, are fairly similar in size and appearance, and are also wiggly little scavengers who make great aquarium cleaners. Each of these fish however, can be distinguished from the Kuhli Loach by their individual color patterns and adult size.

Some of the other members of the Kuhli loach group are the Java Loach (Black Kuhli Loach)Pangio oblonga, the Myer’s Loach (also called Myer’s Slimy Loach or Giant Kuhli Loach) Pangio myersi, Indian Thorneye Pangio cuneovirgata, Half-Banded Loach Pangio semicincta, Shelford’s Thorneye (Borneo Loach) Pangio shelfordii, and another one that is not often seen is the Dwarf Kuhli Pangio robiginosa.

Scientific Classification


Kuhli Loach – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:20 gal (76 L)
Size of fish – inches4.7 inches (11.99 cm)
Temperature:73.0 to 86.0° F (22.8 to 30.0&deg C)

Habitat: Distribution / Background

The Kuhli Loach Pangio kuhlii (previously Acanthophthalmus kuhlii) was described by Valenciennes in 1846. They are found in southeast Asia; Sumatra, Singapore, western Malaysia, Java, Borneo, and Thailand. This species is not listed on the IUCN Red List. Other common names they are known by include Prickly Eye, Coolie Loach, Giant Coolie Loach, Cinnamon Loach, and Leopard Loach.

They live in sandy areas of slow- moving rivers and mountain streams covered in leaf litter. Their habitats are normally shaded from the sun by the forests canopy. In nature these loaches are found in small groups, however they are not schooling fish.

  • Scientific Name: Pangio kuhlii
  • Social Grouping: Groups – Not actually schooling fish, but are usually found in clusters of their own kind.
  • IUCN Red List: NE – Not Evaluated or not listed


The Kuhli Loach is a smaller, worm-like loach that can reach from 3 – 4 1/2 inches (7.8 – 12 cm) in length, though generally a bit smaller in the aquarium. Their life span is generally about 10 years, though they been reported to live even longer.

This loach’s body has a pinkish yellow background color crossed by 12 to 17 vertical dark bars and has three bars on its head. There are no scales on the head, the eyes are covered by a transparent skin with a short spine in front of them, and they have 3 pairs of whisker-like barbels. The dorsal fin is set very far back, and the anal fin is set at the end of the base of the dorsal fin.

Their is also an albino color form of this Loach, known as the Albino Kuhli Loach. This a bred color form, and it is not certain whether the Albino Kuhli Loach occurs naturally in the wild. But these would be highly visible animals, so beacons for predation.

  • Size of fish – inches: 4.7 inches (11.99 cm) – These fish can get up to about 4 1/2 inches (12 cm), though they are usually smaller in the aquarium.
  • Lifespan: 10 years – This fish generally has a lifespan of about 10 years, but has been reported to live longer.

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 Kuhli Loach will generally eat all kinds of small live and frozen foods and meat based foods are relished the most. They also like sinking pelleted and tablet foods, flakes, and a bit of vegetable foods such as algae wafers. To keep a good balance give them a high quality prepared food everyday. Feed tubifex worms, brine shrimp (either live or frozen), mosquito larvae, and daphnia as a treat.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Occasionally
  • 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 about 30% a week are needed for the Kuhli Loach. With your weekly water change make sure to vacuum the gravel to remove all excess food and waste, but It’s best not to remove any bio film on rocks and decor. A magnet algae cleaner normally does a great job in keeping the viewing pane clear.

  • Water Changes: Weekly – 30%

Aquarium Setup

The Kuhli Loach will swim mostly on the bottom of the aquarium, but at night these loaches will swim all over the tank. Never introduce this loach into a biological immature setup as these fish require pristine water. This fish will do well in a medium sized aquarium (ideally 20 gallons or so) with soft, slightly acidic water and subdued lighting. They need good water movement that provides plenty of oxygenation. The tank water should turnover at least 10-15 times per hour. An undergravel filter is a great choice for these fish as it creates high oxygen through out the tank as well as reducing the waste. Adding a canister filter or power head to the setup will make the proper current for this loach.

The decor with for fish is really up to personal taste, but the substrate needs to be a fine gravel or sand that does not have sharp edges. They will also enjoy a bit of peat moss spread over the substrate to simulate the natural mulm found in their native environment. Some smooth water-worn large rocks and stones should be scattered throughout along with a couple pieces of driftwood and some twisted roots will make a great place to retreat. These loaches are very inquisitive and like to explore so make sure to have a lot of caves and crevices. These fish can and will jump out of the tank if given the chance so make sure to have a tight fitting cover.

  • Minimum Tank Size: 20 gal (76 L)
  • Suitable for Nano Tank: Yes
  • Substrate Type: Sand/Gravel Mix
  • Lighting Needs: Low – subdued lighting
  • Temperature: 73.0 to 86.0° F (22.8 to 30.0&deg C) – Though best kept in the 70’s, They can tolerate the low 80°s for a short period.
  • Range ph: 5.5-6.5
  • Hardness Range: 0 – 5 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Bottom – These fish are mostly bottom dwellers but will swim in all areas of the tank at night.

Social Behaviors

This loach is a peaceful community fish and a great scavenger of uneaten foods that settle to the bottom of the aquarium. They hide during the day, but are quite lively and active in the evening. Though they do not school, they will be more likely to come out of hiding if they are kept with some companions. A singly kept Kuhli Loach will seldom be seen. It is recommended that they be kept in small groups of at least 6 or more of its own kind.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – Best kept in groups of 6 or more, if kept singly a Kuhli will seldom be seen.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Monitor
    • Aggressive (): Monitor
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Monitor
    • Safe
    • Shrimps, Crabs, Snails: Safe – not aggressive
    • Plants: Safe

Sexual differences

On mature males the first ray in the pectoral fin is branched and thickened. Adult females are typically heavier-bodied and a little larger then males. Female with eggs will also be plumper.

Breeding / Reproduction

Although they have been bred successfully in the aquarium, not much is known about the breeding habits of the Kuhli Loach. They scatter bright green adhesive eggs underneath floating plants where the eggs then attach to the stems and roots. The eggs have been described by Herbert Axelrod as a type of bubble nest, with each egg enclosed in a bubble. They are not yet bred commercially.

  • Ease of Breeding: Difficult

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 these fish 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 amounts 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 Kuhli 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.


The Kuhli Loach is readily available at pet stores and online, and is moderately priced.



Featured Image Credit: Arunee Rodloy, Shutterstock