The crabs would be about the size of a silver fish and could be spawned in different variants like the tropical fish. The crab (if killed) would drop an item that looks like a crab (maybe could be called raw crab or just crab). The crab could be cooked into cooked crab meat. The lobster could maybe come in different types but they could just be red as well. They could drop a lobster item similar to the crab that could be cooked into lobster meat. The crab traps could be blocks that look like cages that you place in the water. (Not sure how they would be crafted but I’m sure someone could figure that out) You would place the crab traps under water and just wait. After a while when you return to the traps and open them they could have crabs and lobster inside of them.