Gourmet natural food for all marine and freshwater tropical fish * Significantly improves coloration and vitality * Boosts the immune system and aids in disease resistance From the makers of the world's best frozen foods, this fresh seafood and algae mix is a gourmet natural food for all freshwater and marine tropical fish. Formula One Small Pellets are ideal for feeding smaller marine fish from one inch long and Medium Pellets for feeding fish four inches long or more.