Leaf Sheep Sea Slug (Costasiella Kuroshimae) at Tulamben Bali Dive Site

The Sheep of the Sea


“Leaf Sheep” Sea Slug (costasiella kuroshimae)

Where to Spot in Tulamben

Melasti dive site is the best place in Tulamben to see the Leaf Sheep sea slug.


Think you’re looking at a phosphorescent sheep of the future or perhaps a real life Pokemon? Believe it or not, this adorable little critter is actually a species of sacoglossan sea slug! (Yes, you did just see “adorable” and “slug” together in the same sentence). Due to the slug’s cartoonish sheep-like appearance – i.e., tiny black eyes, ear-like feelers, blushing cheeks, and leafy cerata resembling a shaggy wool coat – divers have appropriately dubbed it the “Leaf Sheep” or “Shaun the Sheep” sea slug.


Instead of spending its days roaming the barnyard, this underwater sheep is found meandering along algae-covered reefs near Indonesia, Japan, and the Philippines. The slug can grow up to 5mm in length and is brightly colored as a result of its green diet. The leaf sheep grazes on algae instead of grass, giving it one fascinating talent that it’s land-living counterpart doesn’t possess. This unique creature is one of the only non-plant organisms that is able to perform photosynthesis! The “solar-powered sea slugs” store chloroplasts from the algae in their bodies and use them to create their own energy in a process called kleptoplasty. Bet you’ve never met any farm animals that can do that!

Leaf Sheep Sea Slug at Tulamben, Bali Dive Site

The peculiar leaf sheep makes a spectacular subject for underwater photos (as do many of the other colorful sea critters in Tulamben), so be sure to bring along your own camera or rent one for your dive! To learn more about other aquatic species you can spot in Tulamben, check out our other marine life blog posts.