There is, however, a big problem these herbivorous fishes face when they eat algae. It is not easy to digest! Algae, like all living things, are made up of cells, with each specialized for a certain role. The cells of algae hold complex, large chains of sugars, called polysaccharides (pronounced, "pol-ee-sack-ah-ride"). Different algae have their own, unique composition of these large sugar chains within their cells. To get energy from algae, herbivorous fishes need to break down these large chains. Inside the guts of fish are molecules known as enzymes (think of them as molecular or chemical scissors) that can break these sugar chains into smaller parts fish can absorb into their bodies. There are many different types of these enzymes, functioning like different workers on a construction team. Each enzyme has a specific job in breaking down different parts of algae. However, not all fish have the right kinds of enzymes to break down algae. So, how are they able to get nutrients from algae that are hard to digest?

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