Common name
Siamese algae eater
Scientific name
Crossocheilus oblongus
Category
Freshwater fish
Group
Algae grazers and shark-like cyprinids
Environment
Freshwater
Origin
River systems of mainland Southeast Asia, including Thailand and the Malay Peninsula
Care level
Intermediate
Adult size
Commonly 12–15 cm, with large confirmed Crossocheilus reaching about 16 cm
Expected lifespan
8–10 years
Minimum housing
At least 180 L for one confirmed individual, or 250 L-plus for a group of six or more with long open swimming space
Temperature
22–28 °C
pH
6.0–8.0
Hardness / minerals
Soft to moderately hard
Salinity
Freshwater
Lighting
Normal aquarium lighting
Placement / swimming zone
Species dependent

Identity and search names

Single-species profile for Crossocheilus oblongus. Preserve the permanent AquaNexus ID and route; retain former scientific combinations and trade names only as searchable aliases. Search names include Siamese algae eater, Crossocheilus oblongus, SAE, Crossocheilus siamensis, Crossocheilus langei, Crossocheilus tchangi.

Environment and housing

Long tank with current, oxygen, mature surfaces and a secure lid

Feeding and nutrition

Feeding ecology: Omnivorous grazer; algae and biofilm are only part of the diet, so provide complete sinking and vegetable foods

Feeding routine: Provide complete sinking and vegetable foods daily; algae and biofilm are supplemental, not a complete diet, and every fish must be checked for body condition.

Breeding and reproduction

Reliable home-aquarium breeding is not established; commercial production methods must not be presented as a normal hobby protocol

Breeding plan: Reliable home-aquarium breeding is not established; commercial production methods must not be presented as a normal hobby protocol Parental care: No reliable aquarium parental care documented.

Compatibility plan

Active medium community fish; avoid territorial lookalikes in cramped tanks

Filtration and aeration

Filtration: Use mature biological filtration sized for the adult group and feeding load, with protected intakes and a flow pattern suited to the species.

Aeration: Maintain dependable gas exchange and dissolved oxygen with surface agitation or supplementary aeration while preserving sheltered resting areas.

Maintenance

Test water routinely, remove waste and uneaten food, service filtration without destroying biofilm and review stocking as animals mature.

Adult projected load

Adult projected load includes mature body mass, social-group size, territorial space, oxygen demand, feeding waste and breeding output.

Welfare and risk

Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Keep this record identity-held unless diagnostic characters and provenance confirm Crossocheilus oblongus. Buying a fish as an “algae solution” is not identification.

Main risk: Keep this record identity-held unless diagnostic characters and provenance confirm Crossocheilus oblongus. Buying a fish as an “algae solution” is not identification.

Biosecurity and release

Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.

Overridable warnings

Warnings may be overridden only after adult size, group structure, filtration, aeration, compatibility and maintenance capacity are recorded.

Sources