whatever is in the yard, mostly the compost pile, the garden, and under stuff. Also trout worms and nightcrawlers from walmart, and occasionally thawed bloodworms. I also used to feed true bloodworms from the local mudflats to my saltwater fish when I had em. A couple times a year, various species would become freeswimming and breed. You could net hundreds of pounds of them in a couple of hours. I would only get a couple of pounds, and keep them in a 10 gallon tank with sand, and feed them chunks of fish at night.