Phallostethidae, also known as the priapium fish, is a family of atheriniform fish native to freshwater and brackish habitats in southeast Asia.

Neostethus lankesteri DSC 2968.jpg
Neostethus lankesteri
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Atheriniformes
Suborder: Atherinoidei
Family: Phallostethidae
Regan, 1916[1]

see text

They are small, no more than 3.5 cm (1.4 in) in length, with partially translucent bodies. They are found in fresh and brackish water from Thailand to the Philippines and Sulawesi. They are named for a muscular organ found under the chin of males. This organ, which may possess small testicles, is used together with the pelvic fins to grasp the female during mating. Unlike most other fish, priapium fishes exhibit internal fertilisation,[2] although they are oviparous.[3]


The family Phallostethidae is divided into two subfamilies and four genera:[3][1]


  1. ^ a b Richard van der Laan; William N. Eschmeyer & Ronald Fricke (2014). "Family-group names of Recent fishes". Zootaxa. 3882 (2): 001–230.
  2. ^ Allen, Gerald R. (1998). Paxton, J.R.; Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 156. ISBN 0-12-547665-5.
  3. ^ a b J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. p. 360. ISBN 978-1-118-34233-6.