Superfish Freeze-Dried Mysis (Brackishwater Shrimp) are a natural source of protein and naturally contain chitosan, which supports a healthy immune system. Mysis are an ideal dietary supplement for many species of freshwater and marine fish. Freeze-drying perfectly preserves all nutrients and eliminates pathogens, making it a safe and nutritious food! Give your fish what they eat in the wild by combining freeze-dried food with your regular daily food to provide your fish with a varied diet.