Frozen brine shrimp is the food every fish will eat voraciously. It is good for fresh and saltwater fish. I usually break up a cube in a cup of water, rince it to remove phosphate and then pour that into the tank.
That food is not particularly nutritious so it is not a good idea to feed your fish exclusively with brine shrimp. However, I like feed them brine shrimp once or twice a week and also use brine shrimps for enticing reluctant feeders to eat.
Spirulina brine shrimps have been feed with sprulina to make them more nutritious than the plain variety. I made a quick search and found some information about spirulina enriched and plain brine shrimps: