Catoprion is a genus within family Serrasalmidae, the piranha and pacu family, native to the Amazon and Orinoco basins of South America. The atlas covers 2 species, 5.5–6 in, both called wimple piranha. What sets the genus apart from typical flesh-eating piranhas is a specialized feeding strategy: lepidophagy, or scale-eating. An underslung, protrusible lower jaw lets these fish dart in and shear scales off other fish rather than take flesh, a striking behavioral departure from the rest of the piranha family.
The scale-eating habit makes Catoprion a poor community-tank choice and firmly an oddball/specialist fish rather than a mainstream aquarium species - keepers who take it on are typically working with predatory or species-specific setups. C. mento is the long-recognized species in the trade and literature; C. absconditus is a more recently distinguished species, less documented in aquarium contexts. Conservation status is unremarkable so far, with one species Least Concern and the other Not Evaluated.