Siamese algae eater
Crossocheilus oblongus
The trade name Siamese algae eater sometimes covers other species; check identity and adult size. A social shoaling fish for a planted aquarium with open swimming space.
At a glance
- Scientific name
- Crossocheilus oblongus
- Dutch name
- Siamese algeneter
- Water temperature
- 24–26 °C
- pH
- 6.5–8
- Adult length, up to approximately
- 16 cm
- Experience
- Basic knowledge
- General hardness (GH)
- 5–20 °dGH
- Starting footprint
- 120 × 40 cm
- Swimming or living zone
- Midwater
- Flow
- Moderate, with sheltered areas
This is a documented adult size, not a measured average. SL means body length excluding the tail fin. Sex, origin and cultivated form can affect size.
Care guidance; origin and captive breeding can change requirements. Some ranges are deliberately narrower than natural extremes in the source. Adjust water gradually and keep ammonia and nitrite at zero.
Tank sizes are editorial starting points for adults, not guarantees for a complete stocking plan. Group size, tank height, swimming length and territories may require a larger aquarium.
Origin
Asia — Asia
Habitat & setup
Tropical rivers and tributary waters; provide cover and open swimming space.
Diet
Varied fine pellets or flakes, supplemented with suitable frozen or live food.
Behaviour & grouping
Group, preferably 8–10 or more.
Living with other animals
Other peaceful fish of suitable size, such as small tetras and calm cory catfish, if water requirements match. Avoid predators.
Possible combinations to investigate further
- Dwarf neon rainbowfish
24–26 °C · pH 6.8–7.5
Reproduction
Egg-laying; eggs and fry usually need separate rearing.
A suitable cover helps prevent escape and jumping. Protect intakes for small animals. Do not use copper-based fish medication with invertebrates.
Sources & image credits
Data compiled on: 2026-09-27. Species sources support identity and care; group sources give general starting points. Practical recommendations are an editorial synthesis.
Photo: Crossocheilus_siamensis_by_Ark.jpg — User:Ark pl wiki. CC BY 3.0.