Kuhli Loach

Looks how to spot one

Eel-shaped (anguilliform) loach

A long, thin, worm-like loach with a slightly flattened body, tiny fins set far back and four pairs of short barbels around the mouth for feeling through sand. The eyes sit under a clear layer of skin, and a small folding spine rests just below each one. The scales are so tiny the skin looks smooth. Males have larger, paddle-shaped pectoral fins with some pigment, while females are deeper bodied and a little bigger.23

Personality what they are like

Gentle, shy and sociable. Kuhlis like to pile together in a little tangle under wood or leaves and spend much of the day out of sight, then come out to forage after dark. They do not school tightly like tetras, but a group gives them the confidence to show themselves more often. They leave other fish, plants and adult shrimp alone, though they will snack on eggs or tiny fry.234

Daily activity how busy a day looks

Mostly active at night and around dusk, searching the bottom and digging into soft sand. Many keepers find they become noticeably livelier when the air pressure drops before a storm. With a group and plenty of cover they also venture out during the day, especially at feeding time.24

Grooming and care the hands-on bits

Use fine, smooth sand or very rounded gravel so the barbels and delicate skin are not scratched. Cover the tank tightly and guard filter intakes with a sponge, since these slim fish slip through small gaps. Do regular partial water changes rather than big ones. Feed after lights-out so food reaches them before faster fish take it.23

Home where they are happiest

Tropical, soft and acidic water. A tank with a base of at least 60 x 30 cm (about 54 litres) suits a small group; around 75 litres (20 US gallons) is often suggested for five or more. Temperature about 21 to 30 °C (most sources centre on 24 to 28 °C), pH about 5.5 to 6.5 (they adapt to near-neutral water, and wild relatives live in water as acidic as pH 4), hardness up to about 5 to 8 dGH. Dim light, a sandy floor, leaf litter, driftwood, caves and plants recreate their shaded forest streams and peat swamps.132

Food basics what goes in the bowl

A small bottom forager that sifts sand for insect larvae, worms and tiny crustaceans. In the aquarium give sinking pellets or wafers plus regular live or frozen foods such as bloodworm, daphnia, brine shrimp, microworms or grindal worms. Small feeds in the evening work best.324

Company who they like around

Keep at least five or six together; in the wild they gather in large groups. Good companions are small, calm fish from similar soft-water habitats such as rasboras, small tetras, danios, corydoras and dwarf shrimp. Avoid large or boisterous fish that could eat or bully them.32

The story where it all began

The species carries the name of Heinrich Kuhl, a young German naturalist who sailed to Java in 1820 for the Leiden natural history museum with his friend Johan Coenraad van Hasselt. In less than a year the pair shipped home a huge collection that included around 1,400 fish, but Kuhl died in Buitenzorg (today Bogor) in 1821 at just 23. French zoologist Achille Valenciennes formally described the loach in 1846 as Cobitis kuhlii. It was later moved to the genus Acanthophthalmus, a name meaning 'thorn eye' after the small spine under each eye, and today sits in Pangio, a genus of around 35 slender loaches. In the aquarium hobby the name 'kuhli loach' spread widely during the 20th century, but it was attached to several look-alike species. When the related Pangio semicincta was separated again in 2009, it became clear that the fish sold in shops are mostly semicincta and its relatives from Malaysia, Sumatra and Borneo, while the true Javanese kuhlii is seldom if ever exported because ornamental fish collecting on Java is uncommon.52631

Recognised by the official bits

IUCN Red List

Pangio kuhlii assessed as Least Concern (December 2019)1

IUCN Red List

Pangio semicincta, the species usually sold as kuhli loach, also listed as Least Concern4

Taxonomy

Family Cobitidae (spined loaches), order Cypriniformes. Described by Achille Valenciennes in 1846 as Cobitis kuhlii, later placed in Acanthophthalmus and now in Pangio. P. semicincta was merged with P. kuhlii in 1992 and separated again in 2009 after fresh Javanese specimens showed clearly different colour patterns.3