...your brain. The long-chain fatty acids found in fatty fish, so good foryour brain (and your heart), are also found in seaweed, algae, and phytoplankton. In fact, that's where fish get them from. Various types of seaweed are served in Japanese restaurants as a vegetable and, pressed and dried, as a wrap for sushi. You can buy seaweed dried or in supplements in most health food stores.