Kuhli loaches are one of my personal favorite tropical aquarium fish species and for a good reason! They are a fun and peaceful fish to watch and easy to keep, which means they’re a great choice for beginners and experienced freshwater aquarists.
Keep reading for everything you need to know about kuhli loach care and keeping this small striped bottom feeder in your own aquarium.
|Minimum tank size||20 gal (75 L, long)|
|Temperature||74-79 °F/23-26 °C|
Pangio kuhlii, also known as Acanthophthalmus kuhlii, is commonly referred to as the kuhli loach, the coolie loach, the leopard loach, or the slimy loach.
The kuhli loach is native to the tropical climates of Indonesia and the Malay Peninsula. Here, they live in calm freshwater rivers and clear mountain streams with sand substrates. The water is often quite acidic with pH ranging between 5.5 and 6.5 and warm temperatures. It is usually stained with tannins and shaded by the thick forest canopy.
Kuhli loaches are nocturnal and quite social fish in the wild. While they don’t naturally tend to school, they do enjoy being in small groups with other loaches and surrounded by other peaceful fish. They live on the bottom of the water column close to plants and rocks, sifting through detritus and substrate for food with their four pairs of barbels. Kuhli loaches are extremely cautious and will hide if threatened. They can live up to 14 years and grow to a maximum size of 13 centimeters (5 inches).
Interestingly, the different wild populations of Pangio kuhlii differ so much in yellow and black variations that they may become separate subspecies one day!
Kuhli loaches have a long eel- or snake-like appearance with a yellow body and dark brown/black vertical stripes. They have very small scales across their bodies, with none at all on their heads. Like other loaches, they have barbels around their mouths, which are used to find food on the bottom substrate.
With a maximum length of 10 cm (4 inches) in the aquarium setting, they are one of the smaller loach species you can get for your tank. Male kuhli loaches are very difficult to tell apart from females, but when the females are carrying eggs they usually grow a bit larger and broader than the males.
Kuhli loach requirements
Because they stay relatively small, kuhli loaches don’t need a very large aquarium. Floor space is more important than the amount of water as loaches mostly stay on the bottom of the tank. This means it’s a good idea to go for a longer, rectangular aquarium than a higher one. A minimum tank size of 31.5 inches (80 cm) is a good place to start, but larger is always better. A sand substrate is preferred, so your loach can feed on the bottom without getting injured or having to push gravel out of the way.
In the wild, the kuhli loach lives in big groups in dark habitats with plenty of plants and places to hide. Try to prevent lots of open space in your tank where your kuhli loach will be exposed to bigger freshwater fish! Also, keep your loach in groups of at least 5 as this will help them be more active and present.
Because kuhlis prefer to hide with the group for part of the day, it’s very important to give them enough places in your tank to do so. This doesn’t have to be complicated: a few shrimp caves can be enough to keep them happy. You can also use Indian almond leaves to create natural, dark water with live plants for added coverage throughout your tank.
Remember that as with most fish, the rule is that the more hiding places you supply, the less they will use them. If the environment is very open, your kuhli loach will stay hidden because it doesn’t feel it’s safe enough to come out.
Kuhli loach fish are very peaceful, so be sure to go for calm tankmates. Aggressive fish can scare and possibly harm them, causing them to go into hiding and disappearing for extended periods of time. Other freshwater fish that will get along with your loach are danios, tetras, and gouramis.
It is not recommended to keep any invertebrates with your kuhli loach. They are carnivores and may resort to eating any smaller shrimps or snails that you have in the tank. One idea is having a kuhli loach tank that resembles their natural habitat, with a group of these colorful fish shining on the bottom of your planted aquarium!
Always gauge what your tank size can handle, have an appropriate substrate and filter, and have consistent water quality before buying any new fish.
The kuhli loach loves to bury itself in the sand and emerge at night. It can be alarming when you look at your aquarium and don’t immediately see your loach! There is a very good chance that it is just hiding in the substrate, as long as you already have the proper filtration. Because some filters resemble spaces that your kuhli loach can get into, it is important to buy a filter with a well-protected intake tube. You don’t want your fish getting stuck in the filter!
Because kuhli loaches have small scales, they are more prone to getting diseases. While mostly treatable, you should always have special medication that considers their special body care and give the recommended dosage.
Kuhli loach diet
These loaches are mostly carnivorous. Kuhlis usually accept pellets and flakes, but their diet should also be supplemented with frozen and live foods like blood worms, mosquito larvae, and brine shrimp. Brine shrimp can easily be grown in a separate tank to ensure there is never any food shortage.
Regular fish food usually doesn’t contain all the nutrients they need, so go for some variety! Also be sure to feed foods that are designed to sink in water, like loach pellets, because your kuhlis may not be able to find floating fish foods that stay higher up in the tank.
Having trouble feeding your kuhlis? Try feeding after you’ve turned off the tank lights. As we’ve discussed before, this species is nocturnal and might not come out to eat if they think it’s still daytime. This especially applies if you recently introduced your kuhli loaches and they’re still acclimating to your tank. It is also possible to adjust when they feed. If you begin giving frozen food and pellets during the day, they will get used to a schedule.
Kuhli loach behavior
Kuhlis are one of my favorite fish species not only because of their adorable looks but also because they bring life to the bottom of any tank. They are peaceful towards their own species and other fish, which makes them suitable for even the calmest setups.
Any kuhli keeper will tell you that the most fun part of keeping them in your tank, though, is watching them interact with each other. They love to share hiding places with as many other kuhlis as possible, which means you’ll often see ‘piles’ of them forming in one tiny spot.
No clue where your kuhlis have gone? No need to worry just yet. These fish are known for going into hiding for extended periods of time if you’ve provided soft sand and ample hiding spots. This is especially likely to happen if you’ve just introduced them into the tank.
Breeding kuhli loaches
I have not been able to find any clear reports of kuhli breeding and spawning. It is often recommended to do a water change with slightly cooler water to stimulate spawning behavior, after which the eggs will be attached to plants and driftwood in the tank.
The fry will feed off tiny food particles at first, and you can start supplementing their diet with microworms, eventually moving on to a larger variety of food. The water should be kept clean and water quality should be stable. If you have a more detailed breeding/spawning report, let me know!
The video below shows kuhli breeding behavior. Kuhli loaches are partly nocturnal, hence the red night lights.
If you’re looking for a fun, interesting, and relatively easy-to-keep fish species for a peaceful aquarium, I would totally recommend considering kuhli loaches. If kept correctly, they are a great addition to the community tank.
Cover photo: Nathalie Nyman