Lettuce Sea Slug (Elysia spp.)

The Lettuce Sea Slug (Elysia spp.), also sold as the lettuce nudibranch, is a peaceful, reef safe grazer named for the ruffled, leaf-like folds along its body that really do look like green lettuce. Collected from the Caribbean and Gulf of Mexico, it is a fantastic natural algae control option, especially for tanks battling hair algae and bryopsis. It is also one of the few sea slugs well suited to reef life, since it grazes a range of green algae rather than one fussy species.

Why we love it

• Hard working, natural grazer that targets nuisance green algae including hair algae and bryopsis
• Peaceful and completely reef safe, it will not bother corals or other livestock
• Genuinely fun to watch, with a ruffled lettuce look and a surprising amount of movement
• Solar powered, it stores chloroplasts from the algae it eats and photosynthesizes, a trick called kleptoplasty

Suggested parameters

• Temperature: 24 to 26°C (75 to 79°F)
• Salinity: 1.024 to 1.026 SG
• pH: 8.1 to 8.4
• Alkalinity: 8 to 10 dKH
• Nitrate: keep low and stable, these slugs are sensitive to high nitrate
• Never expose them to copper based medications

Care and placement

• Difficulty: Easy to moderate, the main requirement is a steady food supply
• Best in an established tank with live rock and a healthy growth of green algae to graze
• Lighting and flow: any reef lighting is fine, with low to moderate flow suiting it best
• Screen powerheads and overflows, since slugs can be drawn into uncovered intakes

Feeding

Lettuce sea slugs feed by piercing algae cells and sucking out the contents, working slowly across rock and glass. They do best when there is enough algae in the system to sustain them.

• Grazes green hair algae, bryopsis, and other soft green algae such as Halimeda and Penicillus
• No supplemental feeding is needed if the tank has a good algae supply
• In a very clean tank, target it onto algae patches or run a refugium to keep it fed
• If algae runs out it can slowly starve, so plan for a steady food source

Compatibility and tankmates

• Peaceful and reef safe with corals, inverts, and most fish
• Avoid keeping it with fish or inverts that pick at slugs
• Multiple slugs can be kept together and will often reproduce in a stable tank

Health and acclimation notes

Drip acclimate slowly, since sea slugs are sensitive to swings in salinity and to poor water quality. They will not tolerate copper, so never use copper based treatments in a tank that houses them. Note that despite the nudibranch nickname, this is technically a sacoglossan sea slug, not a true nudibranch.

What you are buying

• You will receive: 1 Lettuce Sea Slug (Elysia spp.)
• Size, colour, and exact species (commonly Elysia crispata or Elysia clarki) can vary between individuals