Anatomy Of Fish

Structural of fish

Fish anatomy is the study of the form or morphology of fishes. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. (Prosser, C. Ladd, 1991). The anatomy of fish is often shaped by the physical characteristics of water, the medium in which fish live.

Head Eyes Fish eyes are similar to terrestrial vertebrates like birds and mammals, but have a more spherical lens because of the refractive index of water. Their retinas generally have both rod cells and cone cells for scotopic and photopic vision, and most species have colour vision. Some fish can see ultraviolet and some can see polarized light. The ancestors of modern hagfish, thought to be

Most fishes have one dorsal fin which located on the back, but some fishes have two or three. The dorsal fins serve to protect the fish against rolling, and assists in sudden turns and stops. The caudal fin is the tail fin, located at the end of the caudal peduncle and can be expressed in a variety of shapes. It is the main fin for propulsion to move the fish forward. Most fish have a homocercal tail, where the fin appears superficially symmetric but the vertebrae extend for a very short distance into the upper lobe of the fin. The anal fin is located on the ventral surface behind the anus to stabilize the fish while swimming. The paired pectoral fins are located on each side, usually just behind the operculum, and are homologous to the forelimbs of tetrapods. The paired fins assist with steering, stopping and hovering. A peculiar function of pectoral fins, highly developed in some fish, is the creation of the dynamic lifting force that assists some fish, such as sharks, in maintaining depth and also enables the "flight" for flying fish. The pectoral fins also aid in walking, especially in the lobe-like fins of some anglerfish and in the mudskipper. The paired pelvic or ventral fins are located ventrally below the pectoral fins and are homologous to the hindlimbs of tetrapods. The pelvic fin assists the fish in going up or down through the water, turning sharply, and stopping quickly. The adipose fin is a soft, fleshy fin found on the back behind the dorsal fin and just forward of the caudal fin. It is absent in many fish families, but is found in Salmonidae, characins and catfishes. Finlets are small fins, generally between the dorsal and the caudal fins also between the anal fin and the caudal