Hypancistrus is a genus of small, boldly patterned suckermouth catfish — the plecos, family Loricariidae — from the Amazon basin, with the atlas's coverage centred on Brazil, Venezuela, Colombia, and Guyana. Species live wedged among rocks and driftwood in fast, well-oxygenated river channels, using their sucker-like mouths to grip surfaces in current, and most stay compact for a pleco, from under 2 in up to around 6.5 in. The genus is best known for striking black-and-white or black-and-yellow patterning — stripes, spots, or a snowflake-like scatter — that makes individual species, and even individual fish, instantly recognisable.
Hypancistrus is one of the aquarium hobby's most prized pleco genera. The zebra pleco (H. zebra), with its crisp black-and-white stripes, is a long-time high-value centrepiece fish, alongside the snowball pleco (H. inspector), King Tiger pleco (H. seideli), and several L-number species such as L199 (H. furunculus). All are cave-spawners that do well in strong current with driftwood and rock cover, and captive breeding is well established given the fish's value. Wild collection of the zebra pleco has long been restricted by Brazilian export law, and the more recent Belo Monte dam has added further pressure by altering flow through its native stretch of the Rio Xingu, leaving it Critically Endangered and captive-bred stock the only sustainable source for the trade; one species in the genus is also a CARES conservation priority.