dubia roaches are pretty incredible. i raise them as feed for fish. they get blended up and crushed and added with several other ingredients to make home made pellet type food.
those are a live food that can take severe neglect. when i deployed to iraq, i simply set them up with a large tub of dog food and a large tub of water gel and left them in the garage. when i got back, to my surprise, not only did they survive, but about tripled in numbers.
the dog food was completely gone, the water gel completely dried, and my wife didnt even know we still had the colony.
they are slow at start, but probably one of the easiest live foods to grow.