I used to breed live red riggler worms. 75% compost 25% shedded newspaper. The only drawback is that I had to throw in some banana peels and leftover apples, which eventually rots. Then I have to go dig it out of the compost/newspaper. It was too disgusting, so I stopped breeding them.
If you have bigger fish, you can breed red cherry shrimps. Before giving the shrimps to your fish, then gut-load a few shrimps with nutrious food. Some people like gut-loading them with bloodworms and flakes.
Blackworms are very popular feeder, but I never looked into them.
Live food is indeed more nutrious (worms/snails/brine shrimp), except live feeder shrimps (ie red cherry shrimp or ghost shrimps) since you need to gut-load them.