Feeding your saltwater fish can be a challenge. You can use baby freshwater fish such as young guppies, but they won't last long in a salt water environment. This makes judging the correct amount to put in your aquarium a little tricky. Mysis shrimp are also very nutritious, but hard to come by. In the summer months, you can toss in any mosquito and gnat larvae you may find. Tubifex and white worms are commonly fed as live food, but these will burrow into the substrate, die and pollute the tank so be wary when you use them. Live foods alone are not enough to keep your fish healthy.
For more information, please read Feeding Your Saltwater Fish.