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