Pearlfish

"Pearlfish" is also used for some Rivulidae, unrelated American freshwater killifish.
Pearlfish
Echiodon rendahli
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Ophidiiformes
Family: Carapidae
Genera

Carapus
Echiodon
Eurypleuron
Encheliophis
Onuxodon
Pyramodon
Snyderidia

Pearlfish is a general name for a variety of marine fish species in the Carapidae family. Pearlfish have been found in tropical waters of the Atlantic, Indian, and Pacific Oceans at depths up to 2,000 metres (6,600 ft) along oceanic shelves and slopes.

Pearlfish are slender fish, distinguished by having dorsal fin rays that are shorter than their anal fin rays. They have translucent, scaleless bodies reminiscent of eels. The largest pearlfish are about 50 centimetres (20 in) in length. They reproduce by laying oval-shaped eggs, about 1 millimeter in length.[1]

Pearlfish are unusual in that the adults of most species live inside various types of invertebrate. Typically, they live inside clams, starfish or sea squirts, and are simply commensal, not harming their hosts. However, some species are known to be parasitic on sea cucumbers, eating their gonads, and they live in their anal pore. Regardless of the habits of the adults, the larvae of pearlfish are free-living among the plankton. Pearlfish larvae can be distinguished by the presence of a long filament in front of their dorsal fin, sometimes with various appendages attached.[1]

Classification

The genera are divided into three major groupings based on their level of symbiosis:

Pearlfish are currently divided into 7 genera and 31 species:

Genus Carapus

Genus Echiodon Thompson, 1837

Genus Encheliophis

Genus Eurypleuron

Genus Onuxodon

Genus Pyramodon

Genus Snyderidia Gilbert, 1905

References

  1. ^ a b Nielsen, Jørgen G. (1998). Paxton, J.R. & Eschmeyer, W.N.. ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 133. ISBN 0-12-547665-5.