However, it is something to consider. Some fish require it, and some fish will merely benefit from the nutrition found in a live diet. It is best to research your fish and it's dietary needs. It is believed that in almost every instance, live food is better for your fish than dry flakes or pellets. If nothing else, live food does not rot at the bottom of the tank muddling your water clarity and quality.
Most pet stores carry brine shrimp exclusively for food.
If not brine shrimp, you may want to try mosquito larvae. You can find these your self in any standing pools of water in the summer. They are small seed-sized bundles that float about in the water. Be sure not to over feed your fish, any uneaten larvae will hatch and fly around your house. For larger fish, you can feed them young goldfish or guppies.