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Pearlfish facts for kids

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Pearlfish
Echiodon rendahli (no common name).gif
Echiodon rendahli
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Ophidiiformes
Suborder: Ophidioidei
Family: Carapidae
Poey, 1867
Sub-families & Genera
  • Carapinae
    • Carapus
    • Echiodon
    • Encheliophis
    • Onuxodon
  • Pyramodontinae
    • Eurypleuron
    • Pyramodon
    • Snyderidia
  • Tetragondacninae
    • Tetragondacnus

Pearlfish are marine fish in the ray-finned fish family Carapidae. Pearlfishes inhabit the tropical waters of the Atlantic, Indian, and Pacific Oceans at depths to 2,000 m (6,600 ft), along oceanic shelves and slopes. They are slender, elongated fish with no scales, translucent bodies, and dorsal fin rays which are shorter than their anal fin rays. Adults of most species live symbiotically inside various invertebrate hosts, and some live parasitically inside sea cucumbers. The larvae are free living.

Characteristics

Pearlfishes are slender, 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 cm (20 in) in length. They reproduce by laying oval-shaped eggs, about 1 mm in length.

Ecology

Pearlfishes are unusual in that the adults of most species live inside various types of invertebrates. They typically 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 living in their anal pores. Pearlfish usually live alone, or in pairs.

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 fins, sometimes with various appendages attached.

Genera

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

  • Echiodon and Snyderidia - free-living
  • Carapus and Onuxodon - commensal
  • Encheliophis - parasitic, fish in this group live in invertebrate hosts found in shallow-water coral communities such as bivalves, sea cucumbers, and starfish.

See also

Kids robot.svg In Spanish: Carapidae para niños

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