鱼类生产都有一定的适温范围,如果低于它的适温范围,就开始停食,不生长。随着水温的连续下降,有些鱼类进入休眠状态;有些暖水性鱼类则受低温影响而致死亡。我国的地域辽阔,北方地区鱼类生长期一般只有半年左右。如黑龙江边缘地区冰封期长达半年之久,对耐寒能力较强的草鱼、鳙鱼、鲢鱼、鲤鱼等,在漫长的冰封期内也难免发生死亡,对不耐寒的罗非鱼类等等尤需采用严密的越冬防寒措施。即使在南方,鱼类的适温期虽较长,但也会出现低温期,如两广部分地区常有1—2个月 Fish production has a certain range of suitable temperature, if it is below the scope of the appropriate temperature, they stop eating, do not grow. With the continuous decline in water temperature, some fish into the dormant state; some warm water fish are affected by the impact of low temperature death. The vast territory of our country, northern fish growth period generally only about six months. Such as the edge of the Heilongjiang Frozen period of up to six months, the ability of the strong cold hardy grass carp, bighead carp, silver carp, carp, etc., in the long freeze period will inevitably occur death, not hardy tilapia And so on, especially the need for rigorous overwintering cold measures. Even in the south, although the suitable temperature for fish is longer, it can also occur in low-temperature periods. For example, some areas in Guangdong and Guangxi often have 1-2 months