在北半球的温带海域.有一种小鱼叫刺鱼,其体型较小,身体细长,最大一般不超过15厘米。有些生活在淡水中,有些生活在海水中。它们生来活泼,敏锐好动。刺鱼的背鳍前面有两根或多根能活动的棘刺,腹部有一根棘刺和一小片鳍刺,全身无鳞,在体侧常有骨片保护。这样有进可攻退可守的 In the temperate waters of the northern hemisphere, there is a small fish called a thorn fish, its smaller size, slender body, the maximum is generally not more than 15 cm. Some live in fresh water and some live in sea water. They are lively, agile. There are two or more active spines in front of the dorsal fins of the barbed fish, a spine and a small fin thorn in the abdomen, and no scales in the body, often protected by bone fragments in the body. This can be offensive and defensive defensive