1. Crayfish can be eaten in all parts except the head, shrimp yellow and shrimp thread. The head of crayfish is the place that absorbs and processes the most toxins, and it is the part that easily accumulates pathogenic bacteria and parasites. It must not be eaten, let alone eaten raw, which will seriously lead to paragonimiasis. Shrimp yellow is the gonad of lobster, which is close to the liver and is easily polluted. Shrimp thread is the intestine of shrimp, which is easy to gather heavy metals and cannot be eaten.

2. Crayfish is an aquatic animal of Crustacea, Decapoda and crayfish. Also known as Crayfish, Red Crayfish and Freshwater Crayfish. Shaped like a shrimp with a hard shell. The adult is about 5.6~11.9 cm long, dark red, with a nearly black carapace and a wedge-shaped stripe on the back of the abdomen. Young shrimps are uniform gray, sometimes with black ripples. Aojiang is long and narrow. The middle part of the carapace is not separated by a mesh gap, and there are obvious particles on the carapace. The forehead sword has lateral spines or the end of the forehead sword is scored.