Alex Mustard / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) hitchhiking on large t-bar nudibranch (Ceratosoma trilobatum) The shrimp gains food source and protection on the toxic seaslug. Bitung, North...

Georgette Douwma / Nudibranch (Ceratosoma trilobatum) Puerto Galera, Philippines.

Linda Pitkin / Nudibranch (Ceratosoma trilobatum) Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / Nudibranch (Ceratosoma trilobatum) detail of chemo-sensory rhinophore, Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Pacific Ocean.

Aflo / Emperor shrimp (Periclimenes imperator) living with colourful Nudibranch (Ceratosoma trilobatum) Numazu, Osezaki, Izu, Japan. October.