(vertebrate zoology) A modified order of actinopterygian fishes distinguished by the reduction of the first dorsal fin to a few flexible rays, the first of which is on the head and bears a terminal bulb; includes anglerfish and allies.
The anglerfishes and their relatives. The first dorsal fin is reduced to a few flexible rays, of which the first is placed on top of the head and bears a terminal bulb or tassel and functions as a fishing lure (see illustration). Luminescent organs may be present, and in some deep-sea species the males are dwarfed and attached as ectoparasites on the females. There are 3 suborders, 15 families, nearly 60 genera, and about 195 known species. See also Actinopterygii.

Anglerfish (Cryptopsaras couesi). (After G. B. Goode and T. H. Bean, Oceanic Ichthyology, U.S. Nat. Mus. Spec. Bull. no. 2, 1895)