Hypoplectrus nigricans, the black hamlet, is a hamlet in the family Serranidae. It is native to shallow parts of the central Western Atlantic Ocean and Caribbean Sea. It grows to about 15 cm (6 in) in total length. It is a simultaneous hermaphrodite, with a breeding strategy known as egg trading. One fish acts as a female and lays a batch of eggs which the other fertilises. The following night, the roles are reversed.