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...

Jurgen Freund / Timelapse of Giant sea cucumbers (Thelenota ananas) moving underwater, with a Giant clam (Tridacna gigas) in the background, Great Barrier Reef, Queensland, Australia, 2015.

Alex Mustard / 2020VISION / A forest of Sea cucumbers (Psolus phantapus) feeding, extended up out of the sediment in Scottish sea loch, Loch Duich, Ross and Cromarty, Scotland, UK, April

Jurgen Freund / Sea apple (Pseudocolochirus violaceus) with tentacles exposed, feeding, Komodo NP, Indonesia, Indo-pacific.

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

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

Jurgen Freund / Eyed / Leopard sea cucumber (Bohadschia argus), close-up of the skin. Lembeh Strait, North Sulawesi, Indonesia.

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

David Shale / Deepsea benthic Sea cucumber (Peniagone sp) with commensal polynoid polychaete, from mid atlantic ridge, depth approx 2600m, June 2010

David Shale / Deepsea benthic Sea cucumber (Peniagone porcella) from mid atlantic ridge, depth approx 2500m, June 2010

David Shale / Underside of deepsea Sea cucumber (Deima validum) from 2500m, mid Atlantic ridge, June 2010

Jeff Rotman / Scarlet Psolus Sea Cucumber (Psolus fabricii), feeding with arm in mouth. Bay of Fundy, Canada, Atlantic Ocean.

Georgette Douwma / Burrowing sea cucumber (Neothyonidium magnum). The massive tentacular crown is the only part that is visible, the rest is buried in the sand. Feeds by picking particles out of the water with the tenta...

Jurgen Freund / Shark fins and Sea cucumbers drying. Philippines.

Pascal Kobeh / Barrel sponge (Xestospongia testudinaria) covered with Lampert's sea cucumbers (Synaptula lamperti). Crinoids and Feather stars (Crinozoa) also on Sponge. Jewel fairy basslets (Pseudanthias squami...

Georgette Douwma / Kaleidoscopic image of Sea apple (Pseudocolochirus violaceus). Komodo National Park, Indonesia.

Tony Wu / Japanese sea cucumber (Apostichopus japonicus), rare albino. Hokkaido, Japan. May.

Georgette Douwma / Lampert's sea cucumber (Synaptia lamperti) group feeding, North Sulawesi, Indonesia.

Georgette Douwma / Candycane sea cucumber (Thelenota rubralineata). North Sulawesi, Indonesia.

Georgette Douwma / Candycane sea cucumber (Thelenota rubralineata) detail. North Sulawesi, Indonesia.

Magnus Lundgren / Wild Wonders of China / Sea apple, eating, using arm to transfer food into mouth. Ninepin Group or Kwo Chau Islands, Sai Kung District of Hong Kong, China

David Fleetham / Sea cucumber (Holothuria pervicax) at night with Red boring sponge (Hamigera sp) in foreground. Hawaii.

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

Georgette Douwma / Yellow sea cucumbers (Colochirus robustus) feeding in current. Triton Bay, West Papua, Indonesia.

Magnus Lundgren / Wild Wonders of China / Japanese spiky sea cucumber (Apostichopus japonicus). Bohai Sea, Yellow Sea. Zhifu Island, Shandong Province, China.

Magnus Lundgren / Wild Wonders of China / Japanese spiky sea cucumber (Apostichopus japonicus). Bohai Sea, Yellow Sea. Zhifu Island, Shandong Province, China.

Nick Hawkins / Orange-footed sea cucumber (Cucumaria frondosa) tentacles, Bay of Fundy, New Brunswick, Canada, July.

Linda Pitkin / Leather coral (Sarcophyton sp.), on a rock with soft corals and Yellow Sea Cucumbers (Colochirus robustus), Triton Bay, near Kaimana, West Papua, Indonesia

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.

David Fleetham / Tiny brittle star (Ophiothrix sp) crawling across Sea cucumber, (Bohadschia argus) Yap, Micronesia.

David Fleetham / Sea cucumber (Bohadschia argus) which has ejected a part of its internal organs called Cuvierian tubules. These significantly sticky strings are a defense mechanism designed to deter predators. Yap,...

David Fleetham / Necklace seastar (Fromia monilis) on Sea cucumber (Bohadaschia argus) Yap, Micronesia.

Sue Daly / Sea cucumber (Stichopus tremulus), Trondheimsfjord, Norway, July.

Sue Daly / Sea cucumber (Cucumaria frondosa), Trondheimsfjord, Norway, July.

Georgette Douwma / Pineapple sea cucumber (Thelenota ananas) on coral reef, West Papua, Indonesia.

Linda Pitkin / Sea cucumber (Pseudocolochirus violaceus) Rinca, Komodo National Park, Indonesia.

Linda Pitkin / Sea Cucumber (Colochirus robustus) Rinca, Komodo National Park, Indonesia

Linda Pitkin / Sea cucumber / Sea apple (Pseudocolochirus violaceus) Rinca, Komodo National Park, Indonesia.

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

Solvin Zankl / Red squamous rock sea cucumber (Psolus squamatus segregatus) Comau Fjord, Patagonia, Chile, Atlantic Ocean

Solvin Zankl / Red squamous rock sea cucumber (Psolus squamatus segregatus) Comau Fjord, Patagonia, Chile, Atlantic Ocean

Solvin Zankl / Red squamous rock sea cucumber (Psolus squamatus segregatus) Comau Fjord, Patagonia, Chile, Atlantic Ocean

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...