Crossocheilus oblongus

Crossocheilus oblongus is one of several related algae-eating cyprinids from mainland Southeast Asia that are closely allied to the true Siamese Algae Eater (C. siamensis/langei). It is a slender, elongated fish with a continuous dark mid-lateral stripe running from the snout to the tail, and like its relatives it is a diligent grazer of soft algae, diatoms, and organic detritus from surfaces.

In the aquarium it is generally more peaceful than the Flying Fox and less prone to the territorial behaviour occasionally exhibited by the SAE in smaller setups. It adapts well to standard community conditions and can serve as an effective algae management fish in planted tanks.

Crossocheilus oblongus is occasionally misidentified in the trade as the true SAE, highlighting the difficulty of distinguishing between species in this genus. Hobbyists should examine stripe characteristics carefully when purchasing to ensure they obtain the desired species.