1, pinching the shell: the shell becomes soft, indicating that it will die after a long time.

2, look at the weight: the weight is reduced, and it is empty, indicating a long death time.

3, look at the legs: crab legs droop, very loose also means that the death time is longer.

Tips:

Crabs must not be eaten when they are dead. When the crab is dying or dying, the oxygen acid in the crab will decompose to produce histamine. Histamine is a toxic substance. With the extension of death time, more and more histamine is accumulated in crabs, and more and more toxic gases are produced. Even if the crab is cooked, this toxin is not easy to be destroyed. Excessive ammonia nitrogen must be excreted from the kidneys, so eating dead hairy crabs is very bad for the kidneys.

People who eat dead crabs may have symptoms such as vomiting, abdominal pain and diarrhea. Even the half-dead "legged crab" is not suitable for eating. The infection rate and degree of metacercaria of Paragonimus larvae in live crabs are very high. Paragonimus parasitizes in the lungs, which can stimulate or destroy lung tissue, cause cough and even hemoptysis. If it invades the brain, it will lead to paralysis.

Extended data:

Crab culture method:

1, tap water can be used. In this season, the temperature is high and the free chlorine volatilizes quickly.

2, different sizes, small molting speed is fast, molting is the most fragile, and it is easy to become food for big crabs.

3. The bottom of the feeding container is covered with dark bottom sand, and aquatic plants can also be put in for climbing and foraging. If there is no land, it is recommended to raise it in shallow water, just over the back. If there is land out of the water, you can choose deep water.

4. Artificial compound feed cannot be artificially fed. Earthworms or minced fish and shrimp can be used to feed fish, whether raw or dry. It is best to feed some grass foods frequently, such as wormwood and Elodea.

Baidu Encyclopedia-Crab-Crab shopping tips