Harttia is a genus of whiptail catfish in the armored suckermouth family Loricariidae, placed in the subfamily Loricariinae alongside the better-known Rineloricaria and Farlowella. The body is slender and strongly depressed, tapering into a long, thin caudal peduncle, and the head carries the sucker-shaped oral disc typical of the family, used to grip rock and wood in flowing water. The atlas covers 26 Harttia species, roughly 3–8.5 in, found across Brazil's coastal and interior drainages and the Guiana Shield in French Guiana, Suriname, and Venezuela.
Few Harttia reach mainstream aquarium shops; the genus is mostly the province of specialist loricariid keepers, who prize species such as Carvalho's whiptail catfish (Harttia carvalhoi) and Hartt's whiptail (H. loricariformis) for their slim, almost snake-like profile and calm, algae-grazing habits. In the aquarium they do best in cool, well-oxygenated water with strong current and a diet built around biofilm and vegetable matter, mirroring the fast rocky streams they graze in the wild. Most assessed species rank least concern, but several, including one currently ranked critically endangered, have small ranges in southeastern Brazil's coastal streams, where damming and siltation are the main pressures.