primal seas nori seaweed for marine fish Essential for all herbivorous fish including Tangs & Angelfish comes in a sealable packet stays fresh for a long time sizes: 4 inch x 4 inch x 20 sheets use 1 sheet every one to two days remove all uneaten food from the tank ideally used on a seaweed clip 100% natural food source great to keep the colour and health right in your fish highly recommened by jbsmarines