There are several different types of Nori algae, but in general they fall into two major categories, roasted and raw. And believe it or not, there is a huge difference between the two. While your algae grazers may not notice a difference during feeding time, some have been known to turn their noses up to the roasted variety because of the taste. The fish will nip at it, but overwhelmingly ignore it because it’s just not appealing. Besides the challenges of getting the fish to eat the roasted Nori, it also lacks a certain nutritional content that is present in the raw form. All of the benefits have been cooked right out. So, if you buy the roasted kind, you might end up with a product that is both nutritionally poor and the fish won’t touch.