in taxon characin cachama Colossoma macropomum itis:639908 black pacu A large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere. It is also known by the names black pacu, black-finned pacu, giant pacu, cachama, gamitana, and sometimes as pacu (a name used for several other related species). colossoma macropomum tambaqui tambaqui Colossoma macropomum requires discussion