水蛭的养殖密度，一般和外界温度有关。温度低时，密度可适当大些；温度高时，密度可适当小些。而在实际养殖时，春季温度偏低，密度应该大些，而由于是放种期，又不可能太大。

　　Leech breeding density, generally related to ambient temperature. At low temperature, the density can be appropriately larger; At high temperature, the density can be appropriately. But in the actual cultivation, the spring temperature is low, the density should be bigger, as is put a period, and can't be too big.

　　The temperature instability is refers to the temperature too low or larger temperature difference between day and night, so can make the leech disease-resistant ability, leech does not adapt or sick. Cold when did not take timely measures, such as cold in pollen season, will cause leeches morbidity or mortality; Not in hot heat cooling measures, such as the water temperature is too high, the sun direct illuminate, etc., can cause leeches loss of appetite, and even death.

　　夏季温度偏高，养殖密度应当小二些，而由于水蛭大量繁殖，又显得养殖水体不足。如果放养密度高于正常密度3 倍以上，必然造成水蛭活动空间相对减小，再加上饵料不足或分配不均，排泄物过多，有可能发生互相残杀，或引起疾病的发生和蔓延。

　　Summer temperature on the high side, breeding density shall be small 2, and the leech blooms, and appear aquaculture ponds. If the density of livestock 3 times higher than that of normal density, inevitably cause leeches activity space is relatively reduced, coupled with lack of bait or uneven distribution, waste too much, likely killing each other, or cause the occurrence and spread of disease.