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Species profile

Sucking Loach

Gyrinocheilus aymonieri

Common names: Sucking Loach

Recognized speciesLoaches
Sucking Loach (Gyrinocheilus aymonieri)

Adult size

Up to 28 cm

Typical adult length 19.6–28 cm.

Up to 28 cm

Countries of origin

  • See all stock from Cambodia
  • See all stock from China
  • See all stock from Laos
  • See all stock from Thailand
  • See all stock from Vietnam

Good fit for your tank?

Good fit for

  • Keepers able to provide at least a 180 cm aquarium with the substrate, current, and cover this loach needs.
  • A mature aquarium where bottom-feeding fish receive targeted food and regular maintenance.

Think carefully if

  • The aquarium is shorter than 180 cm or cannot support the recommended social group.
  • Slow, broad-bodied fish or other territorial algae grazers share the aquarium.

Sucking Loach is a bottom-dwelling loach requiring a 180 cm or longer aquarium, suitable substrate, stable water, and species-appropriate social housing.

Appearance and Identification

An elongated algae grazer with a ventral sucking mouth, a dark lateral stripe, and a brown, grey, or golden trade colour form.

Juveniles graze algae readily, while adults may become territorial and less interested in algae.

Sexes are difficult to distinguish reliably outside breeding condition. Mature females may become fuller through the abdomen, while males of some species develop stronger colour, fin shape, or breeding tubercles.

Tank Requirements

Suggested filter
About 1,600–2,000 litres an hour
Suggested heater
About 400–600 W for this tank
Minimum tank volume
400 litres
Minimum tank length
180 cm
Minimum group size
1
Recommended group size
1
Activity level
High
Flow preference
Moderate
Planting preference
Moderately planted
Hiding places
Yes
Lid recommended
Yes
Jumping risk
Medium

Use a mature aquarium at least 180 cm long with strong filtration, open swimming space, rock and wood grazing surfaces, and separate retreats. Plan for the adult size rather than the small juvenile offered in shops.

Behaviour and Tankmates

Sucking Loach is an active clinging grazer when young but often becomes increasingly territorial as it grows. Adults may chase other bottom fish and attach to slow broad-bodied tankmates.

Keep singly unless an exceptionally large, carefully structured aquarium allows each adult a separate territory.

Strongly territorial as an adult, especially toward similar-shaped algae grazers and other fish using the lower levels.

Use fast, robust tankmates in a large aquarium and monitor closely. Avoid slow flat-sided fish, fancy goldfish, discus, angelfish, and other territorial algae grazers.

Check tankmates for this species

Water Parameters

Temperature
22–28 °C
pH
6–8
GH
3–15
KH
1–10
TDS
60–260
Stability importance
Important

Maintain stable, clean water within the stated range. Oxygenation, low organic waste, and gradual acclimation are more important than forcing an exact pH or hardness value.

Parameter caveat
Match the supplier water during acclimation and change temperature or mineral content gradually. Rare wild-caught loaches may arrive adapted to narrower conditions than the general range suggests.

Feeding

Diet types
Algae Grazer, Aufwuchs Grazer, Omnivore
Feeding frequency
Daily
Preferred foods
  • Natural algae and biofilmUseful for juveniles, though adults may graze less consistently.
  • Algae wafers and vegetable-based pelletsUse as a staple rather than expecting the fish to clean the aquarium.
  • Protein-rich sinking pelletsOffer sparingly as adults become more omnivorous.

Feed as an omnivorous grazer rather than an aquarium cleaner. Supply algae wafers, vegetable-rich sinking foods, natural biofilm, and modest protein foods as the fish matures.

A hungry adult may rasp mucus from slow tankmates. Regular feeding does not remove the need for careful compatibility.

Breeding

Breeding type
Egg Layer, Egg Scatterer
Breeding difficulty
Difficult
Breeding temperature
25 °C
Breeding pH
7
Brood or egg count
Potentially many hundreds of eggs; dependable hobby-aquarium counts are unavailable.
Incubation
2 days
Parental care
None
Baby foods
  • Infusoria or cultured microscopic foodUse when newly free-swimming fry are too small for Artemia.
  • MicrowormsIntroduce once fry actively search the bottom.
  • Newly hatched Artemia naupliiUse after fry are large enough to swallow nauplii.

Home-aquarium breeding is rarely reported. The species is an egg scatterer without parental care, and commercial production may use controlled spawning methods. A very large breeding system and separate fry-rearing facilities would be required.

Habitat and Origin

Geographic origin
Asia, Cambodia, China, Laos, Southeast Asia, Thailand, Vietnam
Natural habitat
Fast Stream, Freshwater River, Rocky Shoreline
Aquarium contexts
Freshwater Aquarium, Species-Only Aquarium, Very Large Freshwater Aquarium
Audience level
Advanced

Classification

Profile type
Recognized species
Genus
Gyrinocheilus
Family
Gyrinocheilidae
Species group
Fish, Loaches

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