Gary Bell/ Oceanwide / Nudibranch (Ceratosoma sp) with commensal Emperor Shrimp (Periclimenes imperator), Philippines

Gary Bell/ Oceanwide / Nudibranch (Ceratosoma sp) with commensal Emperor Shrimp (Periclimenes imperator), Philippines

Gary Bell/ Oceanwide / Tyron's Risbecia (Risbecia tryoni) with commensal Emperor Shrimp (Periclimenes imperator), Milne Bay, Papua New Guinea

Gary Bell/ Oceanwide / Tyron's Risbecia (Risbecia tryoni) with commensal Emperor Shrimp (Periclimenes imperator), Milne Bay, Papua New Guinea

David Fleetham / Giant / Star pufferfish (Arothron stellatus) opening gills to allow the Commensal / Periclimenes shrimp, (Periclimenes sp) to go inside in search of parasites, Bali, Indonesia.

Georgette Douwma / Emperor shrimp (Periclemenes imperator) on a nudibranch (Ceratosoma sp.) Lembeh Strait, North Sulawesi, Indonesia.

Pascal Kobeh / Transparent commensal / Magnificent anemone shrimp (Periclimenes magnificus) on an Anemone tube (Cerianthus sp) Sulu Sea, Philippines

Pascal Kobeh / Female diver taking a picture of a shrimp (Periclimenes sp.) living in a sea pen (Pteroeides sp.) Philippines, Sulawesi Sea.

Norbert Wu / Coleman's Shrimp (Periclimenes colemani) male and female hiding among spines of venomous Fire Urchin (Asthenosoma varium), Ambon, Indonesia

Jeff Rotman / Symbiotic commensal Emperor shrimp (Periclimenes imperator / Zenopontonia rex) living inside the gills of a Spanish dancer nudibranch (Hexabranchus sp), Red Sea, Egypt

Pete Oxford / Spotted Cleaner Shrimp (Periclimenes yucatanicus) on Giant Caribbean Anemone (Condylactis gigantea), Bonaire, Netherlands Antilles, Caribbean

Birgitte Wilms / Shrimp (Periclimenes sp) on Bulb Tentacle Sea Anemone (Entacmaea quadricolor) tentacles, Solomon Islands