The Sera Marin Spirulina Grazer XL, 4.2 oz, is the herbal food for mainly herbivorous fish, such as tangs, angels and wrasses. The carefully manufactured tablets sink to the bottom or can be attached to the aquarium glass by slight finger pressure. This allows for watching even shy fish eat right in front of you. The particularly high amount of spirulina algae (21%) supports healthy digestion and liveliness. The balanced food supports healthy development, splendid appearance as well as the natural behavior of the animals.