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...

David Hall / Brooks urchin shrimp (Allopontonia brooki), commensal among the venomous spines of Variable sea urchin (Asthenosoma varium). On sea floor, Komodo, Indonesia.

David Hall / Soft coral ghostgoby (Pleurosicya boldinghi) swimming through Soft coral (Dendronephthya). Shrimp and benthic Comb-jellies (Ctenophora) present, all commensal. Pantar, Alor Archipelago, Indonesia.

David Hall / Banded tozeuma shrimp (Tozeuma armatum) on Black coral (Antipatharia). Komodo, Indonesia.

Magnus Lundgren / Wild Wonders of China / White stripe urchin shrimp (Stegopontonia commensalis) among the spines of its host sea urchin. Commensal shrimp. Xiaoliuqiu Island, Taiwan

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

Alex Mustard / Portrait of a hidden Corallimorph shrimp (Pliopontonia furtiva) on a coral reef. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

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.