For starters, have you read the Raising Larvae and Microfoods articles on Caudate Central? That pretty much covers food sources. Cage size is really going to depend on HOW MANY. One or two can live in a shoe box, 10-15 can live in a 10-gallon tank, and 100 will require several large tubs. Water depth is a matter of preference and how you manage water quality. If you give more details, you may get better answers. Good luck with it/them!