Lettuce Sea Slug

Geographical Origin and Habitat: Widely distributed in the Caribbean Sea and tropical western Atlantic coastal waters. Inhabits shallow coral reefs, protected lagoons, and seagrass beds.

Taxonomy: Member of the Plakobranchidae family, genus Elysia. Possesses highly folded and ruffled parapodia that increase body surface area to maximize photosynthesis. Reaches about 5-7 cm.

Social Behavior: Peaceful and solitary species. Spends most of its time grazing on algae or basking under bright lights to power its stored chloroplasts.

Coloration and Sexual Dimorphism: Color varies from bright green to bluish or pale yellow with small white spots. Simultaneous hermaphrodite with no visible sexual dimorphism.

Tank Setup: Requires a mature marine aquarium with live rocks and abundant algae growth.

All wavemakers and filter intakes must be screened: to prevent the slug from being sucked in.

Diet and Feeding: Specialized herbivore. Feeds on the sap of green algae like Bryopsis and Derbesia, keeping their chloroplasts functional inside its tissues (kleptoplasty) to photosynthesize energy.

Water Quality: Standard marine specific gravity (1.023-1.025), pH 8.1-8.4, temperature between 22°C and 26°C. Extremely sensitive to elevated nitrates and phosphates.

Compatibility and Tankmates: Reef-safe. Compatible with small, peaceful fish. Avoid gastropod predators such as pufferfish, large wrasses, or opportunistic crabs.

Aquarium Breeding: Hermaphroditic. Mating involves cross-fertilization and the deposition of gelatinous egg spirals. Larval survival in home aquariums is extremely rare.

Risks and Diseases: Intolerant to copper treatments and sudden osmotic shifts. The main hazards are mechanical suction in filtration and starvation in overly clean tanks.