To keep the hairy crabs alive for a few days, the following two methods can be adopted:

1. Refrigeration method: put the hairy crabs tied with crab ropes into the fresh-keeping layer of the refrigerator. In the low temperature environment, the metabolism of crabs will slow down, reduce consumption, and thus live longer. You can use a wet towel to cover the crab to keep it moist.

2. live-rearing method in buckets: for crabs without crab ropes, you can use buckets to raise crabs, and the wall of the buckets is relatively high, so you don't worry about crabs crawling around. Pouring the right amount of water into the bucket can also play a role in moisturizing.