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

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

Fred Bavendam / Spanish Dancer (Hexabranchus sanguineus) nudibranch egg ribbon, Kimbe Bay, Papua New Guinea

Fred Bavendam / Spanish Dancer (Hexabranchus sanguineus) nudibranch pair mating, Hawaii

Juergen Freund / Spanish dancer nudibranch {Hexabranchus sanguineus} egg ribbon, Indo-pacific

Sue Daly / Spanish dancer {Hexabranchus sanguineus}, Red Sea

Constantinos Petrinos / Spanish dancer {Hexabranchus sanguineus} on sandy seabed, Sulawesi, Indonesia

Juergen Freund / Spanish dancer {Hexabranchus sanguineus}swimming, Indo-Pacific

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

Juergen Freund / Spanish dancer nudibranch (Hexabranchus sanguineus) Philippines

Chris Newbert / Shrimp (Periclimenes sp) living among the gills of the Spanish Dancer (Hexabranchus sanguineus) nudibranch, 50 feet deep, Papua New Guinea

Chris Newbert / Shrimp (Periclimenes sp) living among the gills of the Spanish Dancer (Hexabranchus sanguineus) nudibranch, 50 feet deep, Papua New Guinea

Juergen Freund / Egg ribbon of Spanish dancer {Hexabranchus sanguineus} Indo-Pacific

Juergen Freund / Spanish Dancer producing egg ribbon {Hexabranchus sanguineus} Indo-Pacific

Juergen Freund / Spanish dancer {Hexabranchus sanguineus} on a divers hand, Indo-Pacific

Norbert Wu / Spanish Dancer (Hexabranchus sanguineus) nudibranch, Red Sea

Juergen Freund / Spanish dancer nudibranch {Hexabranchus sanguineus} Indo-pacific

Carine Schrurs / Spanish dancer nudibranch eggs {Hexabranchus sanguineus} Anilao, Batangas, Philippines

Carine Schrurs / Spanish dancer nudibranch {Hexabranchus sanguineus} Anilao, Batangas, Philippines

Constantinos Petrinos / Spanish dancer {Hexabranchus sanguineus} Sulawesi Indonesia

Juergen Freund / Spanish dancer {Hexabranchus sanguineus} Sulu-Sulawesi seas, Indo Pacific

Juergen Freund / Spanish dancer {Hexabranchus sanguineus} Sulu-sulawesi seas, Indo Pacific

Juergen Freund / Spanish dancer {Hexabranchus sanguineus} Sulu-sulawesi seas, Indo Pacific

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

Nature Production / Eggs of nudibranch Spanish Dancer {Hexabranchus lacera} laid on coral reef, Red Sea, Egypt

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