What does the crab imply in feng shui?

I don't know much about Feng Shui, but crabs are parasitic diseases.

Pay attention to personal hygiene, take a bath frequently and change clothes frequently. Besides taking medicine in time, you should also wash clothes and bedding with boiling water. Don't eat spicy food. You can use Yujin Xerox Essence Cream and it will be fine in five days. Take a bath every day, change clothes, and observe before and after half a month to see if it will itch again.