The skin of shrimps and lobsters consists of chitin. Because the skin of these animals does not grow with them, they molt regularly. To build up new skin, shrimps eat chitin from the old skin or cellulose from plant material. HS aqua Crusta Chitin+ is a product made from natural shrimp skin and helps to build up new skin. Add a small amount of HS aqua Crusta Chitin+ to the aquarium 3 times a week.