Lettuce Slug

The lettuce sea slug, scientifically known as Elysia crispata, is a unique marine opisthobranch gastropod mollusk native to the shallow tropical reefs, lagoons, and coral cays of the Caribbean and Florida Keys. Reaching an average size of 1.5 to 3 inches (3.8 to 7.5 centimeters) in length, it is named for the elaborate, ruffled parapodia along its back that give it the distinct appearance of a head of curly lettuce. Its coloration is highly variable, ranging from pale green and blue to yellow or creamy white with iridescent spots. Although commonly called a sea slug, Elysia crispata is actually a sacoglossan "solar-powered" sea slug. It possesses a specialized specialized radula tooth that pierces macroalgae cell walls particularly nuisance bryopsis and hair algae species to suck out the internal cellular contents. Through a process called kleptoplasty, the slug retains the intact chloroplasts from the ingested algae within its own digestive tissues, using them to perform photosynthesis under aquarium lighting to generate supplemental energy for itself.