This is a photo of Opae'ula swimming in it's tank. In the background, you see Opae'ula swimming. Also climbing on the rock. The Opae'ula is swimming a lot because they are eating food called Spirulina. It also eats algae on rocks. Opae"ula are red shrimp that eat algae. the shrimp swim up to get its food. Some shrimp turn light color.