freshwater
Siamese Algae Eater
Crossocheilus oblongus
Elongated, torpedo-shaped body with a distinct, unbroken black horizontal stripe running from the snout, through the eye, all the way to the tip of the caudal fin. Above this stripe, the body is a golden-brownish color, while the belly is silvery-white.…
- Habitat
- Native to freshwater streams, rivers, and flooded forest…
- Size & weight
- Typically reaches a length of about 15 centimeters (6 in…
- Diet
- Herbivorous and omnivorous detritivore.…
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Physical characteristics
Elongated, torpedo-shaped body with a distinct, unbroken black horizontal stripe running from the snout, through the eye, all the way to the tip of the caudal fin. Above this stripe, the body is a golden-brownish color, while the belly is silvery-white. They have two pairs of barbels near the mouth and transparent fins.
Habitat & distribution
Native to freshwater streams, rivers, and flooded forests in Southeast Asia, including the Mekong and Chao Phraya river basins. Prefers flowing water with rocky or sandy substrates and abundant vegetation.
Behavior
Generally peaceful and active bottom- to mid-dweller. They can be slightly territorial or semi-aggressive toward conspecifics or similar-shaped bottom dwellers as they mature, but are usually peaceful in groups or community tanks.
Diet
Herbivorous and omnivorous detritivore. Feeds primarily on various types of algae, including stubborn filamentous and red brush algae, as well as biofilms, detritus, and small aquatic invertebrates.
Reproduction
Oiparous egg scatterers. Spawning details in the wild are closely linked to seasonal monsoons and river migrations, though captive breeding is rare and usually hormonally induced in commercial aquaculture.
Ecological role
Acts as an important grazer in freshwater ecosystems, helping to control algae growth on rocks, wood, and aquatic plants.
Similar species
Often confused with the Flying Fox (Epalzeorhynchos kalopterus) and False Siamese Algae Eater (Garra cambodgiensis). The true Siamese Algae Eater has an unbroken black stripe extending to the tail tip, transparent fins, and one pair of barbels (though sometimes two very small ones), whereas lookalikes often have colored fins, shorter black stripes, or more prominent barbels.
Identification tips
Look for the solid black horizontal stripe extending straight through the caudal fin rays, clear/transparent fins, and the lack of bright yellow margins on the fins which are common in lookalike species.
Interesting facts
Unlike many other fish sold as 'algae eaters', the Siamese Algae Eater is one of the few species known to eagerly consume troublesome red brush algae (BBA) in aquariums.