good live foods are daphnia,bloodworm(when possible)blackworm aka tubifix, brine shrimp,freshly hatched and full grown.larger fish can also take earthworms mealworms and crickets,ghost shrimp.real large ones can even eat crawdads(crawfish, crayfish whatever you like to call 'em)some of these you should be careful about.blackworms can be a source of parasites and disease if you get them from wild sources or bad suppliers.brine shrimp should be well rinsed to remove salt before adding to your tank,and i have heard of hydra outbreaks in tanks where baby brine shrimp are used.be careful when feeding earthworms ,be sure that they were raised in a pesticide free enviroment as earthworms eat dirt and the organic matter that is contained in dirt.