Crabs spend most of their time looking for food. They are generally not picky about food. As long as they can get food, they can eat shrimps in eat small fish, but some crabs eat seaweed, even animal carcasses and plants.

Crabs eat other animals, and other animals may eat crabs. For example, humans regard crabs as delicacies, and waterfowl also eat crabs. Some fish like to eat crab feet just like humans.