概述

偶鳍

着生于鱼体左、右侧的成对鳍.位于鳃裂附近的为胸鳍.位于臀鳍前方和腹中线两侧的为腹鳍.肩带支持胸鳍，腰带支持腹鳍.胸鳍一般较大，有平衡作用.鳐类胸鳍扩大与头躯连接构成体盘，成为主要运动器官.硬骨鱼类游泳时，需胸鳍贴身；如骤然停游，胸鳍需举起；如转向游泳，需一侧胸鳍划水，一侧贴身.某些鱼类胸鳍特化，如弹涂鱼胸鳍臂状，用以爬行；飞鱼胸鳍延长如翼，可滑翔.一般腹鳍较小，协助其他鳍作平衡和转弯的作用.腹鳍的位置成为鱼类分类的依据之一.腹位（躯干腹部），如鳓、鲤；胸位（鳃盖后方），如鲈鱼、黄花鱼.喉位（两鳃盖之间），如鳕鱼.潜伏泥沙生活的鱼类，腹鳍变小或消失，如鳗鲡.腹鳍特化为硬棘，如三棘鱼屯.雄性鲨鱼腹鳍内侧特化为交配器.Born in the fish left and right paired fins. Is located in the vicinity of gill slits for the pectoral fin. In the anal fin on both sides of the front and the belly line for the pelvic fins. Strap support for pectoral fins, pelvic support belt. Pectoral generally higher, there is a balance role. skates pectoral fins extended and head and footer to connect the body plate, become a major movement of organs. bony fish swim, the need to close the pectoral fins; if a sudden stop tour, pectoral be raised; such as steering swimming, take the side of the pectoral fin the water, the side next to the skin. specialized pectoral fins of some fish, such as the mudskipper arm-like pectoral fins to crawl; flying fish pectoral fins extended like wings, can glide. the general pelvic fins small, to help other fins for balance and turning role. ventral location in classification is based on one of the fish. bellied bit (trunk, abdomen), such as shad, carp; chest-bit (behind the gill cover), such as sea bass, croaker. throat-bit (two between the gill cover), such as cod. latency sediment living fish, pelvic fins smaller or disappeared, such as the eel. pelvic special into a hard spine, such as the three stickleback tun. male shark fins inside the special device into mating.