Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Gyrinocheilus aymonieri

Sucking loach

Sucking loach, Gyrinocheilus aymonieriSucking loach, Gyrinocheilus aymonieri
Photos by Michelle Stuart and Andy Rapson


Gyrinocheilus: Greek, gyrinos = tadpole + Greek, cheilos = lip

General Notes:

Gyrinocheilus aymonieri isn't actually a true loach. It is a close relative of the loaches but has its own  family - Gyrinocheiliidae, which contains  one genus, with four species. As well as the typical wild form there is a white aquarium morph but both morphs behave in the same way.

Gyrinocheilus aymonieri is very tolerant of wide ranging environmental conditions and from that point of view it is a very very easy fish to cater for. However it is generally to aggressive for most community aquariums and will invariably cause problems when introduced. It is particularly aggressive towards fish which are similar in appearance.

Keeping Gyrinocheilus aymonieri in a group with the aim of spreading the aggression won't normally work, it will make things worse because instead of there being just one trouble maker there will be several.

If you really want to keep this species then the best option s probably a a large species tank (150 gall - 675 litres) with 6 or 7 individuals, good water movement, excellent filtration and a stony substrate with a decor of wood and boulders.


In nature Gyrinocheilus aymonieri will sift through the detritus picking out morsels of food. In captivity it will eat anything and everything, sadly for most new fish keepers the fish they bought as an algae eater will ignore the stuff, instead it will go for a higher quality diet and eat all the usual fish food on offer.
Gyrinocheilus aymonieri are very bold feeders and may try to take over the food for themselves by behaving very aggressively to other fish at feeding time.
Shy timid species won't usually thrive for very long in the presence  of a sucking loach.


Most new aquarist buy Gyrinocheilus aymonieri because it is wrongly sold as an algae eater when it is a couple of inches in length. Initially it will be fine and probably choose to hide and keep a low profile but as it grows it will become increasingly aggressive towards all its tank mates and it won't eat any algae.

Gyrinocheilus aymonieri is a large, drab fish with little to recommend it and a fish which is unlikely to get along with any other species.


There are no reliable external differences between the sexes except when adult and in breeding condition when the male develops tubercules on the head and especially the gill covers and the females will be heavier looking.


Gyrinocheilus aymonieri is commercially bred with the use of hormones. There are no well documented reports of aquarium breeding of Gyrinocheilus aymonieri.

Wild status

The IUCN Red List of endangered species lists Gyrinocheilus aymonieri as 'Least Concern'. The species is very widespread and local threats make little difference to the whole population.
Gyrinocheilus aymonieri is widely collected as a food item. Some are still collected for the aquatic trade but most aquarium fish have been commercially bred with the mutant white morph being the most popular.

Additional information

Despite the name, never rely on any fish with 'algae eater' in its title. Controlling algae is the job of the fish keeper, not the fish. Almost every species which does eat algae will move on to the higher quality diet of fish food given the chance. This is very true of Gyrinocheilus aymonieri.

Information at a glance

pH: 6 - 8
dGH:4 - 25
Temperature: 22 - 28°C (72 - 82°F)
Lighting: Normal
Diet: Omnivore
Size: 28cm (11in), less in captivity.
Min tank size:250 litres
Difficulty level: Easy
Aquarium type: Robust Community or Species tank.
Swimming level: Bottom, on a surface.

Distribution and habitat

distribution map for Sucking loach, Gyrinocheilus aymonieri

Origin: India, Assam and Myanmar to Thailand

Habitat: Medium and large river systems, Inhabits flowing streams and tributaries with substrates of boulders, pebbles, gravel and sand, often in areas with submerged driftwood or tree roots


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Gyrinocheilidae
Genus: Gyrinocheilus
Species: G. aymonieri, (Tirant, 1883)

Other common names:
Chinese algae eater (ironically it doesn't come from China).

Gyrinocheilus pennocki,
Gyrinocheilus monchadskii,
Gyrinocheilus kaznakovi,
Psilorhynchus aymonieri