FishChecker

The Siamese Algae Eater (Crossocheilus oblongus, often incorrectly listed as Crossocheilus siamensis) is a highly sought-after and beneficial freshwater fish, revered by aquarists for its exceptional ability to control various types of algae, including the notoriously stubborn black brush/beard algae. These active and peaceful bottom-dwellers possess a slender, torpedo-shaped body, typically reaching up to 6 inches (15 cm) in length in a mature aquarium. Their most distinguishing feature is a prominent black horizontal stripe that begins at the tip of their snout, passes through the eye, and extends unmistakably into the caudal fin (tail), a key characteristic that differentiates them from similar species like the Flying Fox. Siamese Algae Eaters are excellent community tank inhabitants, generally peaceful with other non-aggressive fish. They thrive in well-oxygenated aquariums of at least 20 gallons (75 liters) for a single specimen, or larger for a group, with plenty of hiding spots provided by driftwood, rocks, and live plants. While primarily herbivorous and dedicated algae consumers, their diet should be supplemented with high-quality flake or pellet foods, blanched vegetables (like zucchini or spinach), and occasional live or frozen foods to ensure optimal health. Keeping them in small groups (3+) is ideal as they are social, and a varied diet prevents them from potentially nibbling on softer-leaved plants if algae sources diminish. Their industrious nature makes them an invaluable asset in maintaining a clean and balanced planted aquarium.

The true Siamese Algae Eater is the only fish that reliably eats Black Brush Algae. Can become territorial with age.