Ever heard of a Java Loach?
This fish, also known as the Black Kuhli Loach, is rarely heard about in the aquarium hobby, though it is very similar to its cousin, the Kuhli Loach (Pangio kuhlii), and they are often kept together in similar setups.
Keep reading to find out everything you need to know about the Java Loach, what makes it different from the Kuhli Loach, and how to keep one of these tropical fish in your freshwater aquarium!
|Java Loach Info
|South and Southeast Asia
|Minimum tank size
|20 gallons (75.7 L)
|72-82° F (22.2-27.8° C)
Pangio oblonga is commonly known as the Black Kuhli Loach due to its similarities in shape, color, and overall close relatedness to the real Kuhli Loach (Pangio kuhlii).
They are also sometimes called the Cinnamon Loach or the Chocolate Kuhli Loach but are mostly known as the Java Loach.
Sometimes these fish may be scientifically referred to as Acanthophthalmus javanicus, though Pangio oblonga is their most recent taxonomic categorization.
For full care requirements for the closely related Kuhli Loach, make sure to check out our care guide here!
The Java Loach can be found throughout many parts of Asia, including Vietnam, Thailand, Indonesia, and as far east as India. There, they can be found in the slowest parts of fast rivers.
At times, they can be seen in huge groups of a few hundred individuals or more, but unlike other loaches, these fish are pretty solitary. They can be found scattered across the muddy bottom of these rivers, scavenging for food on a leaf-littered floor.
Due to abundant organic matter present in the water, these ecosystems are largely blackwater systems with low pH and poor visibility.
In all honesty, Java Loaches aren’t the most beautiful or noticeable fish in the aquarium. That being said, any loach will bring activity and interest to the bottom of your tank!
The Java Loach stays relatively small, growing only to about 3-4 inches (7.6-10.2 cm) at mature size.
They are a dusky brown with a typical snake-like loach body. The underbelly may be lighter in color, though usually, these fish are uniform in base body color.
Due to their wide natural range, coloration may change based on the area of collection.
This has resulted in some pink variations appearing in the aquarium hobby, though these odd-looking scaleless fish might be identified as another species altogether in the future.
Otherwise, there is no difference between either male or female individuals.
Java Loach Tank Requirements
As a type of loach, the Java Loach will spend most of its time sitting on and digging in the substrate of the aquarium.
To prevent injury from the underside of your fish and to allow for burying, it’s best to use a fine and smooth substrate, like aquarium sand. This substrate should be a few inches deep so that your fish can bury itself when it wants to.
Low light vegetation, driftwood, and leaf litter will further help recreate the water conditions this fish is used to living in.
In addition, low lighting and tannins that are added to the water or naturally introduced will help your fish be more present. Though they mostly depend on their sensitive barbels to see where they’re going, some additional blackwater coverage may help this shy fish come out more often.
Java Loaches are peaceful fish and very easy-going. They do not like strong currents and only minimal filtration is needed. Make sure that there are no small openings in your equipment that your loach could mistake for a safe burrow!
If you find that your fish isn’t out in the open as much as you’d like, try making its surroundings more comforting by dimming the lights and adding more organics.
Otherwise, these small fish only need about a 20-gallon (75.7 L) long fish tank. A tight-fitting lid is an absolute must as all loaches can be master escape artists!
Java Loaches are a blackwater species. This means that they are used to areas with high organics, stained water, and a low pH.
In the wild, they can be found in extremely acidic waters with a pH under 3.0. However, in the aquarium, they have been bred to tolerate pH levels closer to neutral, 7.0.
Black Kuhli Loaches are tropical fish and need a stable temperature between 72-82° F (22.2-27.8° C).
Java Loach Tank Mates
Java Loaches can be shy fish, but they’re very compatible with most other species. Due to their blackwater preferences, it’s best to go with other fish that also prefer these conditions.
Here are some of the best species to keep with Black Kuhli Loaches:
- Other Javas
The secret to success with keeping Java Loaches is matching activity levels. These community fish are very calm but easily frightened.
Larger and more aggressive fish will cause your loaches to hide more than you want. While gouramis and angelfish have successfully been kept with Black Kuhli Loaches, it’s best to go with the smaller and more peaceful fish species available.
Also, the Java Loach will highly appreciate being kept in a group though they’re relatively solitary in the wild. It is best to keep at least three of these fish together, though the exact number will depend on the tank size.
In general, these fish are compatible with most community species. That being said, they are loaches and will likely eat any snails, eggs, or fish fry that they happen to come across.
Java Loach Behavior
These fish are shy. So shy that they’ll spend the majority of their time hiding behind logs or completely buried in the substrate; sometimes the only thing you’ll be able to see is a barbel or snoot sticking up out of the sand.
Java Loaches demonstrate very similar behavior to Kuhli Loaches and will stay at the bottom of the tank, regularly sifting through the substrate and swimming to the upper portions of the tank on rare occasions.
Bright lights and loud noises can cause your Java Loach to jump out of the water and aquarium if there is no lid.
Remember that while these fish are peaceful, they’ll eat most invertebrates or small fish they come across at the bottom of the tank.
Java Loach Diet
One of the best things about having Java Loaches is watching them eat!
They have incredibly sensitive barbels that can be used to detect prey in the water and the substrate.
To find food, they filter the substrate into their mouths and expel whatever is not food back into the water via their gills. This way, they take in any organics, leftover food, or microorganisms that might be in that area.
However, your fish won’t be able to sustain itself only on what’s currently available in your aquarium.
Java Loaches absolutely love worms. Live, frozen, and freeze-dried earthworms, blackworms, and bloodworms can regularly be given to your fish. Bloodworms in particular can live in the substrate for some time, making it fun for your fish to display its natural predatory instincts.
Otherwise, Java Loaches will eagerly accept a high-quality freshwater fish flake food or pellet.
Breeding Java Loaches
While Kuhli Loaches and Black Kuhli Loaches have been successfully bred in the aquarium setting, it is rare.
Your fish need to be extremely happy to initiate breeding, and favorable conditions seem to vary from tank to tank.
Some hobbyists say that they’ve had luck with large, smooth gravel that keeps fertilized eggs from getting eaten as opposed to the recommended sand.
Otherwise, keep water quality constant and feed a high-quality, well-varied diet.
Java Loaches aren’t the most common fish to come across at local fish stores, but they have all the attitude and persona of any Kuhli Loach.
In general, these scaleless fish are very easy to keep once they’ve been established in the aquarium.
Maintain group sizes of at least three or more and enjoy watching them hunt for worms on the sandy substrate!
If you have any questions about Java Loaches, any other species of loach, or have had the rare success of breeding a type of loach in your freshwater aquarium, don’t hesitate to leave a comment below!