Siamese Algae Eater

A Siamese algae eater or the Siamese algae eater is currently one of the most popular fish in the aquarium because it is an avid algae eater, which is particularly suitable for the community aquarium. However, this peaceful and useful species is not necessarily suitable for very small aquariums, as it can grow relatively large.


  • Name: Siamese algae eater
  • System: Carp-like
  • Size: about 16 cm
  • Origin: Southeast Asia
  • Attitude: easy to maintain
  • Aquarium size: from 160 liters (100 cm)
  • pH: 6.0-8.0
  • Water temperature: 22-28 ° C

Interesting facts about the Siamese Algae Eater

Scientific name

Crossocheilus oblongus, synonym: Crossocheilus siamensis

Other names

Siamese algae, greenfin barbel, Siamensis


  • Class: Actinopterygii (ray fins)
  • Order: Cypriniformes (carp fish-like)
  • Family: Cyprinidae (carp fish)
  • Genus: Crossocheilus
  • Species: Crossocheilus oblongus (Siamese algae eater)


The Siamese algae eater can reach a total length of more than 16 cm in nature. In the aquarium, however, the species usually remains smaller and rarely grows larger than 10-12 cm.

Shape and color

Many algae eaters of the genera Crossocheilus and Garra are similarly elongated and have a broad, dark longitudinal stripe. Siamese algae eaters can be easily distinguished from other, similar species by the fact that a very broad, dark longitudinal stripe continues to the end of the caudal fin. Otherwise, the fins are transparent and the species is colored gray.


Crossocheilus oblongus usually inhabits fast flowing clear waters in Southeast Asia, where they are also common near rapids and waterfalls. There they graze the algae from the stones. The distribution of the species ranges from Thailand through Laos, Cambodia, and Malaysia to Indonesia.

Gender differences

The females of this algae eater are slightly larger than the males and can be recognized by their more robust physique. The males look more delicate.


The breeding of Siamese algae eaters is usually achieved in breeding farms in Eastern Europe and Southeast Asia through hormonal stimulation. Most of the imports, however, are caught in the wild. There are no reports on reproduction in the aquarium. But Crossocheilus are certainly free spawners who scatter their numerous small eggs.

Life expectancy

With good care, Siamese algae eaters can easily reach an age of around 10 years in the aquarium.

Interesting facts


As in nature, the algae eaters also eagerly graze on all surfaces in the aquarium and primarily eat green algae from aquarium panes and furnishings. Younger specimens should also remove the annoying brush algae, but with age, the effectiveness of the animals as algae eaters decreases. Of course, these fish also eat dry food as well as live and frozen food that is fed in the community aquarium without any problems. To do something good for you, leaves of lettuce, spinach or nettles can be blanched and fed, but they do not attack living aquarium plants.

Group size

The Siamese algae eaters are also sociable schooling fish that you should keep at least in a small group of 5-6 animals. In large aquariums, there can also be a few more animals.

Aquarium size

These algae eaters are not necessarily among the dwarfs among the aquarium fish and should therefore be given a little more swimming space. If you keep a group of animals and would like to socialize them with some other fish, you should have at least a one-meter aquarium (100 x 40 x 40 cm) for them.

Pool equipment

The animals do not make any great demands on the aquarium setup. However, a few stones, pieces of wood, and aquarium plants are recommended, which are eagerly grazed by the animals. You should make sure that there is enough free swimming space, especially in the vicinity of the filter outlet, which the fish, which need a lot of oxygen, like to visit.

Socialize algae eaters

With such peaceful and useful fish you have almost all options with regard to socialization. C. oblongus can be z. B. socialize well with tetras, barbel and bearblings, loaches, viviparous tooth carps, not too aggressive cichlids, and catfish.

Required water values

Siamese algae eaters prefer quite soft water but are so undemanding that they feel very comfortable even in hard tap water. The oxygen content of the water is much more important than the water chemistry because it should not be too low for such flowing water inhabitants. The animals feel most comfortable at water temperatures of 22-28 ° C.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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