Alex Mustard / Commensal emperor shrimp (Periclimenes imperator) moves across the colourful red patterned surface of its host Candycane sea cucumber (Thelenota rubralineata). Misool, Raja Ampat, West Papua, Indonesi...

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...

Jeff Rotman / Symbiotic emperor shrimp (Periclimenes imperator / Zenopontonia rex) living in the gills of a spanish nudibranch (Hexabranchus sanguineus) Red Sea, Egypt

Juergen Freund / Imperial / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) on an Eyed / Leopard sea cucumber (Bohadschia argus). Lembeh Strait, North Sulawesi, Indonesia

Juergen Freund / Imperial / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) on an Eyed / Leopard sea cucumber (Bohadschia argus). Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Imperial / Emperor shrimps (Periclimenes imperator / Zenopontonia rex) on a sea cucumber. Lembeh Strait, North Sulawesi, Indonesia.

Jeff Rotman / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) living inside gills of Spanish Dancer Nudibranch (Hexabranchus sanguineus). Egypt, Red Sea.

Alex Mustard / Emperor shrimp (Zenopontonia rex) female rides on the back of a nudirbranch (Tambja morosa), while picking food from the seabed. Anilao, Batangas marine protected area, Luzon, Philippines. Verde Islan...

Alex Mustard / Pair of Emperor shrimp (Zenopontonia rex / Periclimenes imperator) female is the larger one, hitch a ride on a large nudibranch (Tambja luteolineata) and pick food from the seabed with their claws. Bi...

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

Gary Bell/ Oceanwide / Emperor Angelfish (Pomacanthus imperator) juvenile being cleaned by Scarlet Cleaner Shrimp (Lysmata amboinensis), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Emperor Angelfish (Pomacanthus imperator) juvenile being cleaned by Scarlet Cleaner Shrimp (Lysmata amboinensis), Tulamben, Bali, Indonesia

Georgette Douwma / Emperor shrimp (Periclemenes imperator) on a Sea Cucumber. West Papua, Indonesia. Indo-West Pacific.

David Fleetham / Imperial commensal shrimp (Periclimenes imperator / Zenopontonia rex) on Spanish dancer nudibranch (Hexabranchus sanguineus) at night. Philippines.

David Fleetham / Imperial shrimp (Periclimenes imperator / Zenopontonia rex), two on Sea cucumber (Holothuroidea). Wakaya, Fiji.

David Fleetham / Emperor shrimp (Periclemenes imperator) on a leopard sea cucumber (Bohadschia argus), Indonesia.

Alex Mustard / Emperor angelfish (Pomacanthus imperator) with Cleaner shrimp (Urocaridella sp.) grooming it. South Ari Atoll, Maldives. Indian Ocean.

Franco Banfi / Emperor shrimp (Periclemenes imperator) on sea cucumber (Thelenota ananas) Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Franco Banfi / Emperor shrimp (Periclemenes imperator) on sea cucumber (Thelenota ananas) Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Franco Banfi / Emperor shrimp (Periclemenes imperator) on sea cucumber (Thelenota ananas) Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Franco Banfi / Emperor shrimp (Periclemenes imperator) on sea cucumber (Thelenota ananas) Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Franco Banfi / Emperor shrimp (Periclemenes imperator) on sea cucumber (Thelenota ananas) Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Franco Banfi / Emperor shrimp (Periclemenes imperator) on Sea cucumber (Thelenota ananas), Tubbataha Natural Park, UNESCO Natural World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines. April.

Constantinos Petrinos / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) with parasitic Isopod (Bopyridae) and living commensally with Leopard Sea Cucumber (Bohadschia argus) Lembeh Strait, North Sulawesi, Indonesi...

Linda Pitkin / Emperor shrimp (Periclimenes imperator / Zenopontonia rex), commensal with Amberfish Sea cucumber (Thelenota anax) Lembeh Strait, North Sulawesi, Indonesia.

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

Georgette Douwma / Commensal emperor shrimp (Periclimenes imperator / Zenopontonia rex) hitching a ride on a Nudibranch (Risbecia tryoni). Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / RF - Nudibranch (Risbecia tryoni) with commensal Emperor shrimp (Periclimenes imperator / Zenopontonia rex). Lembeh Strait, North Sulawesi, Indonesia. (This image may be licensed either as rights ma...

Alex Mustard / RF - Emperor shrimp (Periclimenes imperator / Zenopontonia rex) exploring alien-looking landscape of host sea cucumber (Bohadschia argus). Emperor shrimps are commensals on many hosts, including sever...

Alex Mustard / Commensal emperor shrimp (Periclimenes imperator / Zenopontonia rex) scuttles across the skin of its host sea cucumber, Dauin, Dumaguete, Negros, Philippines. Bohol Sea

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

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

Juergen Freund / Imperator commensal shrimp (Periclimenes imperator / Zenopontonia rex) on sea cucmber, Indo-pacific.

Juergen Freund / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) on a chromodoris nudibranch, Bali, Indonesia, Indo-pacific.

Juergen Freund / Imperator commensal shrimp (Periclimenes imperator / Zenopontonia rex) on sea cucmber, Indo-pacific.

Juergen Freund / Imperial / Emperor shrimps (Periclimenes imperator / Zenopontonia rex) on a sea cucumber. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Imperial / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) on a sea cucumber. Lembeh Strait, North Sulawesi, Indonesia.

Tim Laman / Honeycomb moray eel (Gymnothorax favagineus) with mouth open, being cleaned by cleaner shrimp and a juvenile Emperor angelfish (Pomacanthus imperator), Bali, Indonesia

Georgette Douwma / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) camouflaged on sea cucumber, Sipadan, Malaysia.

Georgette Douwma / Nudibranch {Hypselodoris apolegma} (previously H. bullockii) with an Emperor shrimp (Periclemenes imperator) Rinca, Indonesia

Georgette Douwma / Nudibranch {Hypselodoris apolegma} (previously H. bullockii) with an Emperor shrimp (Periclemenes imperator) Rinca, Indonesia

Georgette Douwma / Nudibranch {Hypselodoris apolegma} (previously H. bullockii) with an Emperor shrimp (Periclemenes imperator) Rinca, Indonesia

Georgette Douwma / Nudibranch {Hypselodoris apolegma} (previously H. bullockii) with an Emperor shrimp (Periclemenes imperator) Rinca, Indonesia

GEORGETTE DOUWMA / Emperor shrimp (Periclemenes imperator) and Comb jellies (Coeloplana astericola) on a Luzon starfish (Echinaster luzonicus). Bali, Indonesia.

Georgette Douwma / Nudibranch {Hypselodoris apolegma} (previously H. bullockii) with an Emperor shrimp (Periclemenes imperator) Rinca, Indonesia

Chris Newbert / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) on Sea Cucumber (Euapta sp), Papua New Guinea

David Hall / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) on Spanish dancer (Hexabranchus sanguineous) Indonesia

David Hall / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) on Spanish dancer (Hexabranchus sanguineous) Indonesia

David Hall / Emperor shrimp {Pericllimenes imperator on Sea cucumbe, Papua New Guinea

Chris Newbert / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) on Sea Star, 90 feet deep, Papua New Guinea

Juergen Freund / Emperor shrimp on sea cucumber, Indo-Pacific.

Birgitte Wilms / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) on Sea Cucumber (Synapta maculata) 20 feet deep, Papua New Guinea

Juergen Freund / Emperor cleaner shrimp {Periclimenes imperator / Zenopontonia rex} on sea cucumber. Indo Pacific

Constantinos Petrinos / Emperor shrimp pair on sea cucumber, Sulawesi, Indonesia

Georgette Douwma / Emperor shrimp {Periclimenes imperator / Zenopontonia rex} on sea cucumber, Papua New Guinea

Doug Perrine / Two Emperor shrimps {Periclimenes imperator / Zenopontonia rex} on gills of Spanish dancer nudibranch, Great Barrier Reef, Australia (Non-ex).

Juergen Freund / Emperor shrimp camouflaged on sea cucumberr, Indo-Pacific

Constantinos Petrinos / Emperor shrimp {Periclimenes imperator / Zenopontonia rex} and tiny harlequin crab {Lissocarcinus orbicularis} on sea cucumber {Bohadschia argus} Sulawesi Indonesia

Gary Bell/ Oceanwide / Emperor Shrimp (Periclimenes imperator) on sea cucumber, Great Barrier Reef, Australia

David Fleetham / Pair of Emperor shrimp (Periclemenes imperator) on a sea cucumber, Mabul Island, Malaysia.

Roberto Rinaldi / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) hiding in gills of Spanish dancer nudibrach (Hexabranchus sanguineus), La Runion, Indian Ocean.

Roberto Rinaldi / Emperor shrimp (Periclimenes imperator / Zenopontonia rex) hiding among the feathery gills of a spanish dancer nudibranch / sea slug (Hexabranchus sanguineus), La Runion, Indian Ocean

Juergen Freund / Emperor shrimp {Periclimenes imperator / Zenopontonia rex} on Sea cucumber, Indo pacific

David Hall / Emperor shrimp {Periclimenes imperator / Zenopontonia rex} on Spanish dancer nudibranch, Indo pacific

Birgitte Wilms / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) on Spanish Dancer (Hexabranchus sanguineus) nudibranch, Red Sea, Egypt

Norbert Wu / Emperor Shrimp (Periclimenes imperator / Zenopontonia rex) live on surfaces of Sea Cucumber, Papua New Guinea

Juergen Freund / Emperor cleaner shrimp {Periclimenes imperator / Zenopontonia rex} on sea cucumber Sulawesi, Indonesia

Georgette Douwma / Composite image of marine invertebrates on black background. Top row from left: Tube anemone (Ceriantharia), Yellow sea cucumber (Colochirus robustus), Nudibranch (Nembrotha lineolata), Squat shri...

Alex Mustard / Portrait of a large female Emperor shrimp (Zenopontonia rex/ Periclimenes imperator) on a sea cucumber (Bohadschia sp.). Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea,...

David Fleetham / Emperor shrimp (Periclimenes imperator) riding on side of Sea cucumber (Holothuroidea). Pacific Ocean, Philippines.

Georgette Douwma / Emperor shrimp (Zenopontonia rex) on a Slender T-bar Nudibranch (Ceratosoma gracillium). Tulamben, Bali, Indonesia.