The Siamese Algae Eater (Crossocheilus siamensis) is a longtime favorite in the aquarium hobby due to its active nature and its voracious appetite for various types of nuisance algae, including pesky black beard algae. It is a mostly herviborous fish that is gregarious as a juvenile, but is shoaling (rather than schooling) as an adult. As it matures, a distinct hierarchy develops within a group of this species, and stress and aggression are likely when the group contains less than 6 specimens.

Care is simple for the Siamese Algae Eater. It is tolerant of a wide range of water parameters, but it will thrive in an aquarium with ample filtration and moderate to high water flow. This active fish is known to jump occasionally, so a secure aquarium lid is recommended. It will readily eat most high-quality dry foods rich in vegetable matter, but it should also be offered fresh vegetables such as zucchini and cucumber as well. Meaty foods should be kept to a minimum with this fish.

As stated above, the Siamese Algae Eater is a generally peaceful fish, but it will prey on dwarf shrimp and other very small invertebrates. It does not seem to bother most snails, and we have found it to be generally peaceful with most larger shrimp (such as Amano, Flower, Green Lace, and Vampire Shrimp) as long as they are too large to be considered easy prey. The Siamese Algae Eater is a schooling fish as a juvenile, but can become more territorial with its own kind and similar-looking species as it matures. It must be kept in groups of at least 6 fish to avoid harrassment of subdominant specimens, or else it should be kept singly. Aggression can be kept to a minimum in a larger tank with plenty of territory and cover for each fish.