You don't need to spend money on crabs. I'm not sure where you live, but i live in New England, and around here, if you go to the beach late at night when it's low tide, you can catch hundreds of crabs, there everywhere. I was just at the beach last saturday and caught about 100 crabs in about 20-30 min. I threw all the ones under 3 1/2 inches back which was most of them and took he rest home for feeding to Lola (my octo.) I have a couple plenn plax containers which ive divided the crabs into, then added an air pump to each container, so far they seem to be doing fine, there all still alive. I actually placed 2 smaller crabs in one of my bigger tanks thinking they'd die from the warm water and then my eel would eat them but they surprisingly are still alive and stealing the other fish's food! oh well..