Java Loach is perfect if you like the wiggly action of the kuhli, but with a more streamlined look!

The Java Loach or Black Kuhli Loach Pangio oblonga is sometimes referred to as an ‘unbanded coolie’. It is a uniform reddish brown color on its body and head (slightly lighter on the underside). There is also a single black bar at the base of the tail. It is also referred to as Chocolate Kuhli Loach and Black Kuhli.

As with any of the Kuhli loaches, the Java Loach needs to be introduced into an established aquarium. They won’t do well in a newly set up tank. When first introduced they can be shy, but once they are established and comfortable, they are quite undemanding. They are nocturnal, so get most active at night. They do prefer to be fed at the end of the day.

The Black Kuhli Loach has the typical behaviors of the Pangio genus. It spends its time 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..

They are peaceful with other tank mates, and although the Java Loaches are not a schooling fish, they will be more likely to come out of hiding if you keep them with several of their own species. Having like companionship makes them more prone to behave as they would in nature. They do best in groups of three or more. They are quite hardy and can live for several years.

There are several other interesting unbanded species in the Pangio genera. These include the Pangio borneensis (previously Acanthophthalmus borneensis), and Pangio filinaris (previously Acanthophthalmus filinaris).

Members of the Kuhli loach group with bands including the familiar Kuhli Loach (Coolie Loach or e Cinnamon Loach)Pangio pangia, 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


Java Loach – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:20 gal (76 L)
Size of fish – inches3.2 inches (8.00 cm)
Temperature:73.0 to 77.0° F (22.8 to 25.0&deg C)

Habitat: Distribution / Background

The Java Loach Pangio oblonga (previously Acanthophthalmus Javanicus) was described by Valenciennes in 1846. They are found in Asia; Vietnam, Laos, Cambodia, Thailand, Malaysia and Indonesia. Also possibly from India, Myanmar, and Bangladesh. This species is not listed on the IUCN Red List. Other common names it is known by are Black Kuhli Loach, Chocolate Kuhli Loach, and Black Kuhli.

They live in shallow sandy areas of rivers and streams among leaf debris and the shore vegetation. These loaches are normally found in the shallow, sluggish areas of the streams and possibly live in flooded fields during the high water season. In nature these loaches are not schooling fish, but live as clusters of scattered individuals and feeds primarily on benthic invertebrates.

  • Scientific Name: Pangio oblonga
  • 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


This is a smaller, thin loach that can reach just over 3 inches (8 cm) in length with a life span of about 8 – 10 years. It is a uniform reddish brown color (slightly lighter on the underside), with a single black bar at the base of the tail. It is sometimes referred to as an ‘unbanded coolie’.

The body of the Java Loach is long and worm-like with a dorsal fin that is set way back on its body. It has with four pairs of barbels in the mouth area and no scales on its head. Its eyes that are covered with a transparent layer, giving it protection as is scurries about the sand, and like all of the Cobitidae family of “thorn-eyes”, it has two thorny spines situated between the eyes.

  • Size of fish – inches: 3.2 inches (8.00 cm) – These fish can get up to just over 3 inches (8 cm).
  • Lifespan: 10 years – This fish has a lifespan of about 8 – 10 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 Java Loach or Black 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 Black Kuhli. 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 – Water changes of about 30% weekly.

Aquarium Setup

The Java 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 – Substrate needs to be soft, so use very fine gravel or sand.
  • Lighting Needs: Low – subdued lighting
  • Temperature: 73.0 to 77.0° F (22.8 to 25.0&deg C)
  • Range ph: 6.3-6.5
  • Hardness Range: 4 – 8 dGH
  • Brackish: No
  • Water Movement: Weak
  • Water Region: Bottom – These fish are mostly bottom dwellers but may swim all about 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 Java Loach will seldom be seen. It is recommended that they be kept in small groups of 3 or more.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – Best kept in groups of 3 or more, if kept singly it will seldom be seen.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • 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

Not much is known about the breeding habits of the Java Loach. There has been one documented breeding of this loach in the aquarium, however it was not under controlled conditions. Fry were discovered in the substrate and no spawning or courtship was observed. 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 Java 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 Java Loach or Black Kuhli Loach is often readily available at pet stores and online, and is moderately priced.



 Pangio oblonga (Image Credit: Sahat Ratmuangkhwang, Wikimedia Commons CC BY-SA 3.0 Unported)