Fish fins are the most distinctive features of a fish, composed of bony spines protruding from the body with skin covering them and joining them together, either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. fish can have up to three dorsal fins. The dorsal fins serve to protect the fish against rolling, and assist it in sudden turns and stops. 1  In anglerfish, the anterior of the dorsal fin is modified into an illicium and esca, a biological equivalent to a fishing rod and lure.
emission of electromagnetic radiation during the course of chemical reactions. Such radiation, whether ultraviolet, visible, or infrared, is most commonly generated by oxidation. The radiation can usually be ascribed to the transfer of the oxidation energy to a molecule that is itself not undergoing oxidation.
An oxidation-reduction reaction must occur. Electrons must flow through a separate path from the reaction solutions. Nonparticipating ions must flow to keep the electrons electrically neutral. The metals that form the electrodes must be identical.