Alex Mustard / Yellow tube sponge (Aplysina fistularis) on coral reef, diver exploring in background. Black Rock Drop Off, East End, Grand Cayman, Cayman Islands, British West Indies. Model released.

Alex Mustard / Portrait of a Giant frogfish (Antennarius commersoni) on a large Yellow elephant ear sponge (Ianthella basta). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Jordi Chias / Sponge (Mycale acerata) with diver. Lermaire strait, Antarctic Peninsula, Antarctica.

Alex Mustard / Yellow tube sponge (Aplysina fistularis) on a coral reef, with the camera rotated during the long exposure. East End, Grand Cayman, Cayman Islands. British West Indies. Caribbean Sea.

Alex Mustard / Spotlight goby (Gobiosoma louisae) looking out from inside a Yellow tube sponge (Aplysina fistularis), growing on a coral reef. Bloody Bay Wall, Little Cayman, Cayman Islands, British West Indies. Car...

Olga Kamenskaya / Endemic freshwater sponge (Lubomirskia baicalensis), Lake Baikal, Siberia, Russia. October.

Olga Kamenskaya / Endemic sponge (Lubomirskia baicalensis), Lake Baikal, Siberia, Russia. September 2013

Claudio Contreras / Giant barrel sponge (Xestospongia muta) Cozumel Reefs National Park, Cozumel Island, Caribbean Sea, Mexico, February

Franco Banfi / Orange elephant ear sponge (Agelas clathrodes) Santa Lucia, Camaguey, Cuba, Caribbean Sea, Atlantic Ocean

Alex Mustard / Yellow tube sponges (Aplysina fistularis) growing on a Caribbean coral reef. Cayman Brac, Cayman Islands. Caribbean Sea.

Georgette Douwma / Erect rope sponge (Amphimedon compressa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Stove-pipe sponge (Aplysina archeri) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Erect rope sponge (Amphimedon compressa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Row pore rope sponge (Aplysina cauliformis) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Stove-pipe sponge (Aplysina archeri) and Orange elephant ear sponge (Agelas clathrodes) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Olga Kamenskaya / Diver with Baikal sponges (Lubomirskia baicalensis). Lake Baikal, Russia, March 2007. Model released.

Alex Mustard / Portrait of Blacktip grouper (Epinephelus fasciatus) resting in Barrel sponge (Xestospongia testudinaria) Mabul Island, Sabah, Borneo, Malaysia. Sulawesi Sea.

Franco Banfi / Nudibranch (Cratena peregrina) on a sponge, Ist Island, Croatia, Adriatic Sea, Mediterranean.

Alex Mustard / A long exposure renders Bar jacks (Carangoides ruber) as ghostly trails as they swim around a sponge, on a coral reef, at night. East End, Grand Cayman, Cayman Islands. Overall winner of GDT competiti...

Franco Banfi / Scuba diver and yellow sponges (Aplysina cavernicola) on Brioni Steamship wreck, Vis Island, Croatia, Adriatic Sea, Mediterranean. Model released.

Brandon Cole / Finger Sponge (Raspailia topsenti) and Demoiselle (Chromis dispilus) fish swimming by, 13 feet deep. Poor Knights Islands Marine Reserve, New Zealand, Pacific Ocean.

Sue Daly,Sue Daly / Reef wall with sponge and bryozoan growth, Poor Knights Islands, New Zealand, January

Franco Banfi / Detail of sponge (Chalinula nematifera) Maldives, Indian Ocean

Linda Pitkin / 2020VISION / Yellow staghorn sponge (Axinella dissimilis), Lundy Island Marine Conservation Zone, Devon, England, UK, May.

David Shale / Male and Female glass shrimps on Glass sponge (Hexactinellida) from coral seamount, SW Indian Ridge, Indian Ocean, December 2011

Alex Mustard / Caribbean spiny lobster (Panulirus argus) scampers across a coral reef amongst sponges, Bloody Bay Wall, Little Cayman, Cayman Islands. British West Indies, Caribbean Sea.

Alex Mustard / Lionfish (Pterois volitans) sitting on the rim of large sponge on Bloody Bay Wall, Little Cayman, Cayman Islands, Caribbean Sea.

Alex Mustard / Yellow tube sponge (Aplysina fistularis) top view of tubes with water swirling around them, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / A diver exploring a coral reef with formation of brown tube sponges (Agelas conifera) red rope sponges (Amphimedon compressa) and deepwater sea fans (Iciligorgia nodulifera) East End, Grand Cayman, Ca...

Jeff Rotman / Yellow tube sponge (Aplysina fistularis) Red Sea, Egypt

Brandon Cole / Luxurious invertebrate growth on coral reef at 120 feet deep. Crinoids (Davidaster) mixed among many species of sponges and coral. Dominica, Caribbean Sea, January.

Brandon Cole / Giant Barrel Sponge (Xestospongia muta) on top of reef is a fish cleaning station. Small yellow fish in background (juvenile Bluehead Wrasses, Thalassoma bifasciatum) swarm about, remove parasites and...

Juergen Freund / Massive barrel sponge (Xestospongia testudinaria) and diver. Tubbataha Reef National Marine Park, Palawan, Philippines, April 2009. Model released.

Juergen Freund / Elephant ear sponge (Ianthella basta) with a Triplefin blenny resting on it, West New Britain, Papua New Guinea.

Juergen Freund / Detail of Orange elephant ear sponge (Agelas clathrodes) with crinoid / featherstar attached, Kimbe Bay, West New Britain, Papua New Guinea.

Juergen Freund / Brown tube sponge (Agelas tubulata) in the reef, North Sulawesi, Indonesia.

Juergen Freund / Nudibranch (Jorunna funebris) feeding on its preferred sponge, Kimbe Bay, West New Britain, Papua New Guinea

Juergen Freund / Giant barrel sponge (Xestospongia testudinaria) studded with crinoids / featherstars with diver in the background, Kimbe Bay, West New Britain, Papua New Guinea.

Juergen Freund / Details of Orange elephant ear sponge (Agelas clathrodes) with crinoids / featherstars attached, Kimbe Bay, West New Britain, Papua New Guinea

Georgette Douwma / Barrel Sponge (Xestospongia testudinaria) on coral reef with soft corals (Scleronephthya sp), gorgonian and Lyretail anthias (Pseudanthias squamipinnis). Komodo National Park, Indonesia.

Wild Wonders of Europe / Banfi / Striped blenny (Parablennius rouxi) looking out of an encrusting sponge covered hole, Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Wild Wonders of Europe / Banfi / Striped blenny (Parablennius rouxi) looking out of a hole in a rock covered with encrusting sponge, Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Wild Wonders of Europe / Banfi / Striped blenny (Parablennius rouxi) looking out of hole in rock covered with encrusting sponge, Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Wild Wonders of Europe / Banfi / Close-up of rock covered with encrusting sponge (Spirastrella cunctatrix) and (Phorbas tenacior) Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Tim Laman / Orange sponges grow under the overhanging roots of Red Mangrove trees {Rhizophora mangle} Kostrae Island, Federated States of Micronesia.

Wild Wonders of Europe / Pitkin / Yellow encrusting anemones (Parazoanthus axinellae) and sponge (Haliclona mediterranea) 'Turtle Rock', Passage du Cavallo, Lavezzi Archipelago, Corsica, France, September 2008 Wild Wonders kids book.

Wild Wonders of Europe / Pitkin / Yellow encrusting anemones (Parazoanthus axinellae) and sponge, 'Turtle Rock', Passage du Cavallo, Lavezzi Archipelago, Corsica, France, September 2008

Wild Wonders of Europe / Pitkin / Nudibranch / Sea slug (Discodoris / Peltodoris atromaculata) feeding on a sponge (Petrosia ficiformis) Cala di Grecu, Lavezzi Islands, Corsica, France, September 2008