The food that crabs eat mainly includes the following categories:
1. Seafood: Other small aquatic organisms such as small fish, insects, shrimp, scallops, oysters, etc. provide abundant protein and nutrients for crabs.
2. Plants: Aquatic plants such as aquatic plants, algae, seagrass, etc. provide crabs with necessary vitamins and minerals, helping to maintain their dietary balance.
3. Animal carcasses: including the carcasses of other crabs, which engage in scavenging behavior, helping to maintain the cleanliness of the water and providing them with an additional source of protein.
Some crab species also eat sediment in water to obtain organic matter.