八、鱼蛭　　鱼蛭俗称土虫或黑虫,是石斑鱼养殖中偶尔见到的一种外寄生虫。淡水、海水中均有分布。海水性品种较少。1.病因鱼蛭类似于陆栖的水蛭,体扁平细长,长约2～5cm,具环节,能游泳运动。体躯前后各具一个吸盘,前吸盘较小,由口部周围肌肉形成,用来吸附于宿主以吸食血液... Eight, leeches leech commonly known as soil worms or black worms, groupers is occasionally seen in the breeding of an ectoparasitoid. Freshwater, seawater are distributed. Seawater species less. 1. etiology leeches similar to terrestrial leeches, flat and slender, about 2 ~ 5cm, with links, can swim. Body before and after each with a sucker, sucker smaller front, formed by the muscles around the mouth, used to adsorb to the host to take blood ...