Ok, 1, it is best to use a fish tank with a cover to prevent crabs from escaping and lobsters from jumping out of the tank. It's better to keep them separately, otherwise they will kill each other. 2. Plant a water plant and put some pebbles and sand to simulate their outdoor living environment more realistically. Stones should stick out of the water, so that crabs can climb up to bask in the sun and have a rest. 2. Feed crabs with bread crumbs, potato chips, steamed bread slices, rice, small fish and shrimp. Feed lobsters with small fish, shrimp and ham sausage. 3. Change the water once a week, fish them out with small fish net and put them in their hands. It is best to use natural tap water, river water and lake water. If not, use tap water that has been dry for two days. Water should not flow from behind.