Java Loach

Black Kuhli Loach, Chocolate Kuhli Loach, Black Kuhli

Family: Cobitidae Java Loach, Pangio oblonga, Black Kuhli Loach, Chocolate KuhliPangio oblongaPhoto © Animal-World: Courtsey Ken Childs
Latest Reader Comment - See More
I accidentally became a breeder of black kuhli loaches... I started with 3 of them (all that was available). I have a 55g tank that has been running fish since... (more)  texastkc

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.

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

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Cypriniformes
  • Family: Cobitidae
  • Genus: Pangio
  • Species: oblonga
Java Loach - Quick Aquarium Care
  • Aquarist Experience Level: Intermediate
  • Size of fish - inches: 3.2 inches (8.00 cm)
  • Minimum Tank Size: 20 gal (76 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 73.0 to 77.0° F (22.8 to 25.0° C)
Enter a Freshwater Aquarium
  • My Aquarium - Enter your aquarium to see if this fish is compatible!
Popular Searches

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° 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
    • Slow Swimmers & Eaters (): Safe
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Safe

Sex: 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.


Author: Clarice Brough CFS
Lastest Animal Stories on Java Loach

texastkc - 2018-11-01
I accidentally became a breeder of black kuhli loaches... I started with 3 of them (all that was available). I have a 55g tank that has been running fish since August. I have river rock substrate. In addition to the kuhlis, I have platys, guppies, pristella tetras, a gourami and a young angel, a bn pleco, some snails...yeah that's about it. I have some live plants and some moss balls. My ph is usually around 7 and I don't even know my hardness levels. Basic tank, right? A few weeks ago, my oldest son thought he saw something wiggling around in the rocks along the glass wall. By the time I got over to look, it was gone. A few days later, I saw something too and the face made me think kuhli, but reading online says that is rare and I don't have prime conditions (the rock instead of sand, etc.). This week, I have kuhlis out and about that are about half the size of my original 3. I have some much smaller ones that still go down into the rocks. And I still see faces among the rocks that are very tiny. I have accidentally been breeding kuhli loaches. Reading about others who have had the same experience, it seems the river rock is great for breeding as the eggs fall down and provides protection until they get to size. I also tend to overfeed which means feeding debris for adults and babies. I also tend to move my rocks so I create moving holes for movement. There is also a theory that the livebearers in the tank may be producing pheromones that stimulate breeding. Funny thing is that none of my platy or guppy fry make it more than a day or two because of the tetras and the angel who are always hunting. They have shown zero interest in the young kuhlis. Right now I have at least 5 baby khulis, but each day I'm seeing possibly more. Hard to be sure since they keep disappearing into the rocks!

Latisha - 2017-07-28
I have 3 Loaches and when I woke up to feed the rest of the fish I saw 3 or 4 babys swimming around!!! Im so excited I wonder if there are more!! I dont want to move anything to look! I have a 55 gallon with no aggessive fish and the babys are big enough to survive!

daphne - 2010-02-22
Two of my seven loaches are getting busy as I type! I have a few aquariums, but the one in question is a simply, a fully live planted tank with only a few snails, some harlequin rasboras, and the loaches. One of the largest loaches is swimming in a circular pattern, up and down, along the left vertical wall of the tank. These two have been doing this for days. From what I've read, this is the beginning of the mating cycle.

It is set to rain in a few days, and an expert told me to do small water changes until then. When the weather is supposed to change, I am to do a thirty to forty percent water change, and then over the next couple of days I am to watch for floating eggs at the water's surface. I use elodea and other floating plants, so I hope the eggs will last until I find them.

If these two get it on, I'll get back to you!

In the meantime, here's my advice:

Buy the loaches in large, uneven amounts, of over nine. Keep the water warm, flowing, and full of live plants. If you must have other fish in the tank, make sure they are small. Buy a few caves, or bury plastic cups or terra cotta planters halfway in sand.

I wish you the best of luck with your loaches!

P.S. Buy frozen bloodworms once a month, at least. They LOVE them.

  • Shareallicu - 2010-10-09
    Hi, I am new to keeping Kulhi loaches. I saw them at the pet store and thought they looked interesting and fun: I was looking for something a little different from the "regular" type fish, of which I've kept most of my life.

    I asked the salesman if they liked companionship or if they were social amongst themselves (so I would buy more than one) he said no. I had a feeling he was wrong, but didn't want to buy too many if they were aggressive to each other. So I bought two.

    They burrowed together and laid next to each other ALL The TIME! I found that my instincts were right in the first place! They were social. So i went back about 2 weeks later and just bought 2 more. I will be watching them to see how the 4 get along.

    I wish I read your comment about keeping a lot of them together beforehand, but live and learn i guess hehe.

    I will give them bloodworms tonight, thanks for the info! :)
  • vic - 2013-06-07
    I have had two lots of baby java loaches and all doing great. They live under the under gravel filter and they enter and leave via the up tubes of the filter. I notice that they will gather in one place on top of the gravel with their heads in the gravel all within a two inch area. They will do this once or twice a month.
  • vic - 2013-11-11
    Since last I wrote I find now that I now have yet another batch of babies. At this rate I will have more than I can handle. Bye for now.
Trey - 2011-08-20
Is it strange that my loach likes to sit directly under my black skirt tetras as if its schooling with them?

  • Kellie Gates Dewey - 2012-05-06
    Loaches are communal fish. Meaning that they do well with all fish (for the most part) but also can be schooling fish. Since my loach is completely nocturnal, and I NEVER see it in the daytime, I bought another loach so that it does better. If your loach is more of a daytime fish, I would say that it would be fine and normal for your loach to 'school' with your tetras.
markii - 2011-03-01
Hey I'm just wondering where can I buy one I live in ireland and I'm looking for one any suggestions?

  • Jason Lucas - 2011-03-20
    Go to one of the many websites that ship tropical fish internationally I just bought a black kulhi loach today and they are interesting little critters and very easy to take care of, supplement their diet with algae wafers they love them.