16/06/2026
Meet the lettuce sea slug (Elysia crispata)! 🥬
At first glance, it looks like a nudibranch, but it isn’t closely related to them at all! This remarkable sea slug can grow up to 5 cm long and comes in a variety of colors, from green and blue with red, pink, and yellow details. It’s ruffled body gives it the appearance of lettuce, hence the name lettuce sea slug!
What sets this slug apart is a mechanism called kleptoplasty. As it feeds on algae, it retains the algae's chloroplasts and stores them within its own tissues. These stolen chloroplasts can continue functioning inside the slug, allowing it to temporarily harness energy from sunlight.
The chloroplasts can remain active for up to 40 days, but the slug still needs to eat!
The lettuce sea slug is another reminder that there is always more to the reef than meets the eye🐌