Structure of fins

• The fins constitute the major propulsive/locomotory organs in fishes.
• These are either folds of skin or projections from the body surface.
• The fins are supported by fin rays.
• The supporting rays may be bony, cartilaginous, fibrous or horny.
• There are mainly two types of fins in fishes: 1.Unpaired or median fins and 2.paired fins.
• The unpaired or median fins include dorsal fin on the back, an anal fin on the ventral side behind the vent and caudal fin at the end of the tail.
• The paired fins are the pectorals and pelvic or ventrals corresponding to the fore and hind limb of the terrestrial vertebrates.