Sure there is! It is called Live Rock and copepods (or amphipods if you well)

Some chaeto in a 'fuge kind of works too. It'll grow pods in enormous proportions and the pods will slowly escape the 'fuge and enter the display tank where they will quickly get gobbled up.
My all time favourite method for automatic live feeding are shrimps. Cleaner Shrimp, peppermint shrimp, fire shrimp, etc. Get a pair or 3, they breed like rabbits and release baby shrimp into the water column every few weeks. The fish and coral love the feast

I have a boat load of inverts that breed all the time. 3 pom pom crabs, 4 skunk cleaner shrimp, two fire shrimp, 4 sexy shrimp, 3 peppermint shrimp. They all breed like mad and pollute my water column with free fish food all the time.
