They are excellent for fish who have lost their appetite. Frozen foods are also the foods closest to the items the fish would eat in the wild. Brine shrimp, plankton, krill, and bloodworms can be found in frozen form. A fish can obtain a good deal of nutritional value from a natural live food. Some fish are carnivores and benefit from hunting and catching this type of food.
Live foods are excellent for bringing fish into breeding condition.
The movement of the live food will also encourage finicky, new, or sick fish to eat. Be careful in feeding insects to your fish without proper research. Some insects are actually poisonous to fish. Mealworms can be fed to certain varieties such as the African Butterflies. Nightcrawlers and red wiggler worms can be fed to larger varieties of fish.