Kuhli Loaches are by far one of the most comical and unique fish in the aquarium hobby. Despite their relatively large size, reaching 10cm in length, these loaches are completely peaceful and non-destructive. For this reason, Kuhli Loaches are often kept alongside smaller fish species. These loaches require remarkably little space and a group of 6 can be kept in an aquarium with base dimensions 60cm x 30cm. On top of that, these fish are undemanding in terms of water chemistry and will except a wide range of parameters. A pH of between 3.5 and 8.0, hardness of 0 – 143 ppm and temperature between 21 and 30 degrees will suit these fish well.
Kuhli Loaches are most commonly found in shallow, slow-moving forest streams and other still water habitats (swamps, oxbows, and backwaters). These environments are often associated with ancient peat swamps and the decaying organic matter found in the peat swamps results in the water in the surrounding streams being stained dark brown with humic substances. However, Kuhli Loaches are also found in clear waters, which may or may not be tannin-stained to some extent. Both habitats have similar water chemistry. The water often has a negligible dissolved mineral content, is poorly buffered and pH can be as low as 3.0 or 4.0 due to the gradual release of tannins and organic acids from decaying plant material. These habitats are typically shaded from the sun by marginal vegetation and the dense forest tree canopy overhanging the water. Depending on locality the substrate may be composed of peat, mud or sand with the fish typically abundant in piles of leaf litter.
In Malaysia, sympatric species include; Cyclocheilichthys apogon, C. repasson, Garra borneensis, Osteochilus hasseltii, Paracrossochilus vittatus, Rasbora argyrotaenia, R. dusonensis, R. kottelati, R. sarawakensis, ‘Puntius‘ johorensis, ‘P.‘ kuchingensis, ‘P.‘ pentazona, Sundadanio margarition, Trigonopoma pauciperforatum, Pangio anguillaris, P. piperata, Syncrossus hymenophysa, several Gastromyzon, Homaloptera and Nemacheilus spp., Betta akarensis, Sphaerichthys osphromenoides and Carinotetraodon salivator.
Kuhli Loaches prefer a soft, sandy substrate as they have a tendency to dig and may spend time completely buried. Any excavation that does occur will not disrupt rooted plants. Coarser gravel causes these fish to become stressed and may damage the sensitive underside of these fish. Driftwood should also be used, as this will provide shady spots and hiding places for these fish to rest. The addition of dried leaf litter is beneficial to these fish, as it provides additional cover and aids in simulating natural conditions. Marginal vegetation in the natural habitat of this fish prevents most light from entering the water. In order to replicate these conditions, fairly dim lighting should be used. Fluorescent T5 lights should never be used, as these are too bright.
Gentle filtration providing a little surface agitation is adequate and high flow rates best avoided. Ensure that the filter intake is well covered, as even larger specimens are able to squeeze through impossibly small gaps. Small filter bags can be used to cover the intake pipe. Also ensure that the tank is covered as most loaches do jump at times, especially when introduced to a new environment.
Kuhli Loaches are chiefly micro-predators which feed on insect larvae, small crustaceans and worms. A proportion of their natural diet also consists of organic detritus and plant material, which is found in the gut of their prey. In the aquarium Kuhli Loaches will accept sinking dried foods but should also be offered regular meals of live and frozen Daphnia, Artemia, bloodworm, micro worm, grindal worm, black worm, etc.
Behaviour and Compatibility
Kuhli Loaches are peaceful, both with each another and with other fish. There are no existing reports of them harming tank mates, however, they may prey on eggs or fry. In nature they’re often found in large aggregations and in captivity will often pack themselves into a single nook, cranny or cave when at rest, so a group of at least 5-6 specimens should be the minimum purchased. The larger the number of individuals kept, the more active these fish will be during the daylight hours. Thus, a hobbyist who wishes to see these fish during the daytime should keep at least 10.
Small, peaceful species from similar environments such as Boraras, Sundadanio, Rasbora, Trichopsis, Sphaerichthys, Kottelatlimia, etc., constitute the best tank mates. However, these loaches can be kept with a wide variety of other species, as long as, the other species are peaceful and small enough not to consider the Kuhli loaches as food. Some sand-dwelling loaches from the family Nemacheilidae are also suitable but proper research is essential as some can be excessively competitive, territorial or otherwise aggressive. Similar consideration should be taken before purchasing other catfish/loach species.
Adult females are typically heavier-bodied and a little larger than males, while in mature males the first pectoral-fin ray is branched and thickened.
Note from Author
These are beautiful fish which do not often receive the appreciation that they deserve. For anyone looking for a bottom dwelling, peaceful species for small or large community aquariums, I highly recommend the Kuhli loach.