Looking for a bottom dweller to add to your freshwater aquarium, but need a species that’s small and unobtrusive? We’ve got just the fish for you: the kuhli loach (also called ‘coolie’ loach) is peaceful, easy to care for, nice to look at, and a little elusive.
Kuhli loaches are fun to keep, but don’t bother anyone and will not grow to a large size. That’s why we think they’re among the ‘cool’est freshwater fish around!
Below, you’ll find everything you need to know to keep your loaches happy and healthy, so they can reach their full lifespan of a whopping 10+ years.
| Name (common, scientific) | Kuhli loach, coolie loach, Pangio semicincta (or incorrectly: Pangio kuhlii) |
| Minimum tank size | 15 gallons |
| Minimum group size | 6 |
| Temperature | 71.5-79 °F (22-26 °C) |
| pH | 4-7 |
| Difficulty level | Easy |
Kuhli loach description & natural habitat
Description
Here’s a unique-looking fish you’ll recognize the moment you spot it in your local aquarium store! Kuhli loaches form part of a genus called Pangio, which in turn belongs to the family of true loaches (Cobitidae).
Like other Pangio loaches, kuhlis are small (up to 4″ in length) and elongated, almost like baby snakes. They sport a mostly muddy brown body with incomplete vertical yellow bands (up to 12) and a pale belly.
The species’ dorsal fin is placed quite far back, and they tend to use their pectoral fins for support and to move around. The tentacle-like barbels on their face, typical for bottom feeders, help them forage in muddy and sandy substrates.
Tip: Kuhli loaches, like other loaches, possess a pair of spines below their eyes. They can become entangled in nets when you catch them, and they can even pierce your skin. If you ever have to catch yours, you should do so very carefully.
Will the real kuhli loach please stand up?
It’s a frequent occurrence in the aquarium hobby: taxonomic confusion. Fish can be named incorrectly or misidentified when they’re imported, and sometimes, these mistakes stick. The kuhli loach is a prime example of this.
This species’ common name is derived from its supposed scientific name, Pangio kuhlii, which in turn is an homage to a 19th-century German naturalist called Heinrich Kuhl.
The problem? Many experts now suspect that Pangio kuhlii never actually made it into the aquarium trade. The fish sold as kuhli loaches are likely actually Pangio semicincta, and possibly other Pangio species (there are 30+ in total).
In fact, the whole thing is pretty confusing in general—at one point, P. kuhlii and P. semicincta were actually considered to be the same species. However, a 2012 article concluded that they are different. Categorizing species is not easy sometimes!
Does all this matter? Not that much. The real Pangio kuhlii and its close cousin Pangio semicincta inhabit similar habitats and need similar conditions to thrive. However, we just like calling things by their proper name.
Natural habitat
Assuming that the kuhli loaches we keep in our tanks are indeed Pangio semicincta, they are naturally found in Indonesia (Borneo, Sumatra), Malaysia (Borneo, mainland), and possibly slightly into Thailand.
In their natural range, these little loaches inhabit slow-flowing streams and swamps. These habitat types are characterized by their soft substrates, usually covered in mud or half-decayed leaf litter, and their dense aquatic and margin vegetation.
The water in these regions can be stained very dark due to tannins released by decaying plant material. It’s also usually soft, highly acidic, and relatively shaded.
The IUCN Red List considers Pangio semicincta to be a species of Least Concern. The wild population may be under pressure due to human activity, though. Agricultural activity, damming, deforestation and the like still cause serious habitat degradation in the kuhli’s natural range.
Kuhli loach aquarium
If you’d like to keep kuhli loaches in your aquarium, you’ll be glad to know that they’re considered easy to care for. However, it is important to keep their natural habitat in mind. As we’ve discussed, they’re from relatively dark, soft-bottomed and gently flowing waters that are very soft and have a low pH.
A large tank isn’t needed, because these guys stay small and don’t swim around all that much. A 15-gallon is fine for a sizeable group of up to 10 kuhlis. Just make sure it’s fully cycled before introducing any livestock!
Tip: If your tap water is hard (total dissolved solids over 250) or alkaline (pH over 7.5), you may have to take measures to soften and acidify it. Kuhlis are adapted to thrive in waters with a TDS as low as 0 and a pH as low as 3.
Substrate
You don’t necessarily need to set up a Southeast Asian blackwater biotope for your kuhlis to thrive (although they’d certainly appreciate it very much!). However, they will definitely at least need a soft substrate. Sand with a layer of leaf litter, such as Indian almond leaves, would be ideal.
Sharp gravel will damage their delicate mouth barbels, which can lead to nasty infections and even make them unable to feed. Plus, it doesn’t allow them to display their typical burrowing behavior, which would be a pity because it’s quite fun to watch.
Decor
In addition to a suitable substrate, kuhlis really want plenty of cover. A planted aquarium would be ideal. You can add floating plants to dim the light and then go for low-light options such as Java fern and Cryptocoryne for the rest of the tank.
You can finish your aquascape with natural rocks, driftwood, and shrimp tubes for the kuhlis to hide in. Lastly, pop a lid on that tank and add a cover to strong filters to prevent accidents—these fish can jump out of the water or be sucked into the filter.
Tankmates
As we’ve mentioned, one of the reasons kuhli loaches are so cool is that they’re totally peaceful and unobtrusive. The worst they’ll do is eat their tankmates’ eggs or fry, but that’s something no fish can really resist.
These loaches naturally live in groups, and they’ll appreciate as many of their own kind as possible in the aquarium as well. Get at least 6, but preferably (and tank size permitting) more. It’s pretty fun to see them happily pile up like noodles inside a tube or under a rock!
As for other tankmates, any species that doesn’t bother the kuhlis and does well in similar waters is suitable. For an Asian biotope, you can try schools of the small and colorful Boraras and Rasbora, as well as dwarf gouramis for the upper water layer.
If you don’t mind mixing localities, many other tropical species will also work well:
- Small tetra species
- Dwarf cichlids (Apistogramma, Pelvicachromis)
- Peaceful catfish (L-numbers, twig cats, Ancistrus, Corydoras)
- Snails
- Shrimp such as Amanos and Neocaridina
Did you know? Lost your kuhli loach and assume it died? Don’t be so sure. These fish are adept at hiding and can burrow into fine substrate, sometimes popping up years after they were given up for dead. We always assumed this was an exaggeration until it happened to us! The “dead” fish came out to eat at night and burrowed during the day.
Kuhli loach diet
Kuhlis are sand-sifters. They find their food by browsing through leaf litter and mud in search of edible morsels, taking in mouthfuls of the substrate and spitting it back out after they’ve extracted any bits they can eat. In the wild, they mostly consume worms, larvae, small crustaceans, and other tiny bugs.
In the aquarium, your loaches will usually accept commercial sinking foods like small soft pellets and flakes for carnivores/omnivores. They will also highly appreciate regular feedings of frozen or even live foods. Kuhlis love worms.
If you don’t see your kuhli loaches come out during feeding time and you’re worried they’re not getting enough, try a nightly feeding. Around an hour after you’ve turned off the tank lights should work well.
Breeding kuhli loaches
No luck here, unfortunately. Although we’ve seen reports of baby kuhlis popping up without interference on the part of the aquarist, there’s no actual solid information. No one seems to have found out yet how to get these fish to reproduce.
Kuhli loaches sold in the aquarium trade are generally captive-bred, but this is done commercially by means of hormone injections that stimulate the fish to spawn.
Frequently asked questions
It’s not easy to tell the difference between male and female kuhli loaches. However, if you keep a larger group, you’ll notice that the girls are a bit larger and chunkier than the boys.
These loaches have a pretty impressive lifespan of 10+ years! We’ve got individuals in one tank that are at least 12 and still going strong at the time of writing.
Kuhlis aren’t the type of fish to buy if want to sit next to your tank all day watching them. They like to burrow and are mostly nocturnal—although we do spot ours regularly even in our heavily planted aquarium, and it’s always a delight. If yours have gone AWOL, try checking the tank at night.
Yeah, they do that! Check the water quality in your tank using a liquid water test kit. If nothing appears to be amiss, it’s just one of those things. They seem to like gulping air at the surface and they can go mental when the weather shifts or you perform a water change.
Conclusion
Kuhli loaches are one of our favorite freshwater fish species, and after reading this care guide, you’ve probably understood why.
Want a beautiful freshwater aquarium full of colorful fish like the kuhli loach, but don’t know where to start or don’t have the time? We at FantaSEA Aquariums get our hands wet so you don’t have to. Contact us with your aquarium dreams and we’ll make them come true!
Sources & further reading
Kottelat, M. (2012). Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei). Raffles Bulletin of Zoology.
