ancistrus

Ancistrus is a genus of freshwater catfish in the family Loricariidae, commonly known as armored catfish or plecos. These fish are native to South America, found in a variety of freshwater habitats including rivers, streams, and flooded forests. They are characterized by their bony plates covering their bodies and the presence of sucker mouths, which they use to attach to surfaces and scrape algae.

Species within the Ancistrus genus exhibit a wide range of sizes and colorations, though many are relatively small, typically reaching between 4 to 10 inches in length depending on the species. They are often omnivorous, with algae forming a significant part of their diet, but they also consume small invertebrates, decaying plant matter, and commercial foods. Their sucker mouths are adapted for rasping food from rocks, wood, and other surfaces.

Ancistrus are popular in the aquarium hobby due to their algae-eating capabilities and generally peaceful demeanor. Many species are nocturnal or crepuscular, meaning they are most active during dawn and dusk, often hiding in caves or driftwood during the day. They are typically hardy fish but require well-oxygenated water and a varied diet to thrive. Breeding in captivity is common for many Ancistrus species, often involving males guarding eggs laid in a protected cavity.