Siamese algae eater
Crossocheilus oblongus
FreshwaterFish
Care at a glance
- Temperature
- 68–79°F
- 20–26°C
- pH
- 6.0–7.5
- Adult size
- 6.3 in
- 16 cm
- Minimum tank
- 37 gal
- 140 L
- Temperament
- Peaceful
- Social behavior
- Shoaling
- Swim level
- Bottom
- Difficulty
- Medium
- Breeding
- No record
- Rarity
- Common
- Family
- Cyprinidae
- Origin
- Thailand, Malaysia
Overview
These are bottom-oriented schooling fish, so keep a small group of five or more in a tank of at least 140 liters to allow for their adult size. They are peaceful and active and spend the day grazing surfaces. They eat algae, including black beard algae when young, but you must supplement with sinking pellets, wafers, and frozen food. They want clean, soft, slightly acidic water with steady flow.
In the wild
Siamese algae eaters come from fast, clear streams and flooded forests in Thailand and Malaysia. The water there is soft, slightly acidic, and well oxygenated over rocks and leaf litter. Match that with good flow, clean water, and a temperature in the low to mid-20s C. Smooth surfaces and driftwood give them places to graze.
Good to know
Crossocheilus oblongus is a cyprinid, related to barbs and danios. It grows larger than people expect, up to around 16 cm as an adult. It is widely sold but has no reliable record of breeding in home aquariums. Look for the clean black stripe running into the tail, which helps tell it apart from similar look-alikes.
Did you know
Young Siamese algae eaters are one of the few fish that will actually eat black beard algae, which is why they are popular with planted-tank keepers. As they grow, their appetite for it fades and they switch to easier prepared foods.
Weekly picks
Tank mates
Siamese algae eater is a peaceful, shoaling species that keeps to the bottom. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.
Arulius barb
Dawkinsia arulius
Freshwater4.7 in (12 cm) · 37 gal (140 L)66–77°F (19–25°C)
Striped panchax
Aplocheilus lineatus
Freshwater4.3 in (11 cm) · 30 gal (115 L)72–77°F (22–25°C)
Bengal loach
Botia dario
Freshwater5.1 in (13 cm) · 37 gal (140 L)73–79°F (23–26°C)
Flag cichlid
Mesonauta festivus
Freshwater5.9 in (15 cm) · 37 gal (140 L)75–82°F (24–28°C)
Pike topminnow
Belonesox belizanus
Freshwater7.9 in (20 cm) · 44 gal (165 L)73–82°F (23–28°C)
Giant brochis
Brochis britskii
Freshwater3.5 in (9 cm) · 40 gal (150 L)70–79°F (21–26°C)
Common questions
What size tank does a Siamese algae eater need?
A Siamese algae eater needs at least 37 gal (140 L). It spends most of its time in the bottom.
What temperature and pH does a Siamese algae eater need?
A Siamese algae eater is comfortable at 68–79°F (20–26°C) with a pH of 6.0–7.5.
How big does a Siamese algae eater get?
An adult Siamese algae eater reaches about 6.3 in (16 cm).
Does a Siamese algae eater need a group?
Yes. A Siamese algae eater is a shoaling species and should be kept in a group, not singly.
Related species
6.3 in (16 cm)53 gal (200 L)64–77°F (18–25°C)Silver flying fox
Crossocheilus reticulatus
6.3 in (16 cm) · 53 gal (200 L)
4.7 in (12 cm)42 gal (160 L)72–79°F (22–26°C)Borneo black-lobe algae eater
Crossocheilus nigriloba
4.7 in (12 cm) · 42 gal (160 L)
5.9 in (15 cm)32 gal (120 L)68–81°F (20–27°C)Cambodian log sucker
Garra cambodgiensis
5.9 in (15 cm) · 32 gal (120 L)
4.7 in (12 cm)29 gal (110 L)57–68°F (14–20°C)Doctor fish
Garra rufa
4.7 in (12 cm) · 29 gal (110 L)
6.3 in (16 cm)37 gal (140 L)68–79°F (20–26°C)Flying fox
Epalzeorhynchos kalopterum
6.3 in (16 cm) · 37 gal (140 L)
6.3 in (16 cm)66 gal (250 L)73–81°F (23–27°C)Harlequin sharkminnow
Labeo cyclorhynchus
6.3 in (16 cm) · 66 gal (250 L)