Optimal food source and color enhancer for small Angelfish, sponge feeders, and other marine fish with softer mouth parts. Red Marine Algae is a nutritious supplement for all grazing fish, rich in vitamin C, and is 100% digestible. This product should be used as a supplement to other food sources. We strongly recommend using seaweed in combination with Ocean Nutrition Formula Foods (Formula One, Formula Two, Spirulina Formula, etc.).