养殖户在养蟹过程中，常有一些河蟹栖居在远离水面的洞穴里，懒得出来活动觅食，且个体较小。据笔者多年对养蟹池的观察，主要是由以下原因造成的。1养殖水体溶氧太低河蟹对水体的溶氧要求需保持在5毫克/升以上，溶氧过低就会引起河蟹不吃食、不蜕壳；当水中溶氧低于4毫克/升时 Farmers in the process of raising crabs, crabs often live in some caves far from the water, too lazy to feed out activities, and the individual smaller. According to the author for many years observation of crab pool, mainly caused by the following reasons. 1 aquaculture water dissolved oxygen is too low crab water dissolved oxygen needs to be maintained at 5 mg / l above, too low dissolved oxygen will cause the crabs do not eat, do not molt; when the dissolved oxygen in water is less than 4 mg / l