I've cultured and fed red wigglers (AKA composting worms) for years. I have mostly new world cichlids but any fish who can eat worms / high protein food can eat them.
The size of the culture bin (rubbermaid) is one of the constraining factors in their culture rate. They can double in a month in warm weather and with lots of food. They take a month or so to settle down and reproduce.
Red wigglers reproduce and are much easier, in my experience, than nightcrawlers or other worms.
I haven't bought live or frozen food in years...
Matt