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.

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...

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

Georgette Douwma / Stove-pipe sponge (Aplysina archeri) 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.

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

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

Sergio Hanquet / Yellow umbrella slug (Tylodina perversa), two feeding on Golden sponge (Aplysina aerophoba). Tenerife, Canary Islands.

Sergio Hanquet / Yellow umbrella slug (Tylodina perversa) on Golden sponge (Aplysina aerophoba). Tenerife, Canary Islands.

Sergio Hanquet / Yellow umbrella slug (Tylodina perversa) feeding on Golden sponge (Aplysina aerophoba). Tenerife, Canary Islands.

Sergio Hanquet / Yellow umbrella slug (Tylodina perversa) on Golden sponge (Aplysina aerophoba). Tenerife, Canary Islands.

Franco Banfi / Yellow tube sponge (Aplysina fistularis) Dominica, Caribbean Sea, Atlantic Ocean

Franco Banfi / Elephant ear sponge (Ianthella basta) with a scuba diver swimming in he background, Gorgonia Wall Reef, Cabilao Island, Bohol, Central Visayas, Philippines, Pacific Ocean.

Franco Banfi / Spotted moray eel (Gymnothorax moringa) inside Yellow tube sponges (Aplysina fistularis) Dominica, Caribbean Sea, Atlantic Ocean.

Tony Wu / Yellow elephant ear sponge (Ianthella basta) with unique lighting to make it resemble a sculpture, Hornbill Channel in Milne Bay, Papua New Guinea.

Pete Oxford / Yellow tube sponge (Aplysina fistularis) Lighthouse Reef Atoll, Belize Barrier Reef, the second largest barrier reef system in the world. Belize.

Franco Banfi / Red fan corals (Paramuricea clavata), Yellow gorgonian, (Eunicella cavolini) and Yellow cave-sponges (Aplysina cavernicola), Ischia Island, Italy, Tyrrhenian Sea, Mediterranean.

Claudio Contreras / Yellow tube sponge (Aplysina fistularis) Cozumel Reefs National Park, Cozumel Island, Caribbean Sea, Mexico, January

Claudio Contreras / Row pore rope sponge (Aplysina cauliformis) Cozumel Reefs National Park, Cozumel Island, Caribbean Sea, Mexico, February

Claudio Contreras / Yellow tube sponge (Aplysina fistularis) Cozumel Reefs National Park, Cozumel Island, Caribbean Sea, Mexico, February

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

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

Georgette Douwma / Convoluted barrel sponge (Aplysina lacunosa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

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

Georgette Douwma / Convoluted barrel sponge (Aplysina lacunosa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Coral reef scenery with Orange elephant ear sponges (Agelas clathrodes), Stove-pipe sponge (Aplysina archeri) and Boulder brain coral (Colpophyllia natans) Bonaire, Netherlands Antilles, Caribbean, A...

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

Georgette Douwma / Convoluted barrel sponge (Aplysina lacunosa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Convoluted barrel sponge (Aplysina lacunosa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Coral reef scenery with Orange elephant ear sponge (Agelas clathrodes), Stove-pipe sponge (Aplysina archeri) and Azure vase sponge (Callyspongia plicifera) Bonaire, Netherlands Antilles, Caribbean, A...

Pascal Kobeh / Diver on drop off with Stove-pipe sponges (Aplysina archeri), San Salvador Island / Colombus Island, Bahamas. Caribbean. June 2013.

Franco Banfi / Yellow sponges (Aplysina cavernicola) on propeller pt the wreck 'Vassilios T', Vis Island, Croatia, Adriatic Sea, Mediterranean

Franco Banfi / Wall covered with Sponges (Verongia / Aplysina cavernicola) and Red gorgonia (Paramuricea clavata) Ischia Island, Italy, Tyrrhenian Sea, Mediterranean

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

Franco Banfi / Red seafan (Paramuricea clavata) Yellow gorgonian (Eunicella cavolini), Yellow sponges (Aplysina cavernicola) and Yellow cluster anemone (Parazoanthus axinellae) Punta Sant'Angelo dive-site, Ischia Is...

Pete Oxford / Long-spine Porcupinefish (Diodon holocanthus) in Stove Pipe Sponge (Aplysina archeri), Bonaire, Netherlands Antilles, Caribbean

Pete Oxford / Sponge (Aiolochroia crassa), Jardines de la Reina National Park, Cuba

Pete Oxford / Yellow Tube Sponge (Aplysina fistularis) group, Xcalak National Reef Park, Mahahual, Quintana Roo, Mexico

Fred Bavendam / Sponge (Verongia lacunosa), South Caicos, British West Indies, Caribbean

Pete Oxford / Yellow Tube Sponge (Aplysina fistularis), Lighthouse Reef, Belize

Alex Mustard / Yellow tube sponge (Aplysina fistularis) portrait, Grand Cayman, Cayman Islands, Caribbean Sea.

Alex Mustard / Scuba diver exploring the Kittiwake shipwreck, with dense growth of colourful sponges including Row pore rope sponge (Aplysina cauliformis) and Branching tube sponge (Pseudoceratina crassa), Seven Mil...

Alex Mustard / Scuba diver exploring the Kittiwake shipwreck, with dense growth of colourful sponges including Branching tube sponge (Pseudoceratina crassa) and Yellow tube sponge (Aplysina fistularis),Seven Mile Be...

David Fleetham / Yellow elephant ear sponge (Ianthella basta) with dark-coloured Whiteline sea cucumbers (Synaptula lamperti) and the paler, unnamed species, Philippines.

Alex Mustard / Sponge spider crab / Decorator crab (Inachus sp) on Sea vases (Ciona intstinalis). Kinlochbervie, Sutherland, The Highlands, Scotland, United Kingdom. Loch Inchard, The Minch, North East Atlantic Ocea...

Alex Mustard / Sponge spider crab / Decorator crab (Inachus sp) clambers over Sea vases (Ciona intstinalis). Kinlochbervie, Sutherland, The Highlands, Scotland, United Kingdom. Loch Inchard, The Minch, North East At...

Sergio Hanquet / Golden sponge (Verongia aerophoba) Tenerife, Canary Islands.

Claudio Contreras / Scattered pore rope sponge (Aplysina fulva), Cozumel Island, Caribbean Sea, Mexico.

Alex Mustard / A reef scene with an orange elephant ear sponge (Ianthella basta) and red sea whip (Ellisella sp) with schooling silversides fish above. Pelee Island, Misool, Raja Ampat, West Papua, Indonesia. Ceram...

Alex Mustard / A yellow tube sponge (Aplysina fistularis) growing on a Caribbean coral reef, withsun burst above. East End, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Franco Banfi / Rebreather diver exploring the sunken Brioni steam passenger/cargo ship, which sank in February 1930, with yellow sponges (Aplysina cavernicola), south-eastern coast of Vis Island, Croatia, Adriatic S...

Franco Banfi / The big propeller covered with yellow sponges, (Aplysina cavernicola) on wreck Vassilios T, Vis Island, Croatia, Adriatic Sea. July 2019.

Franco Banfi / Rebreather diver exploring the stern of the Italian tugboat Ursus which sank on 31 January 1941, covered with yellow sponges (Aplysina cavernicola), near Stoncica lighthouse, Vis Island, Croatia, Adri...

Franco Banfi / Rebreather diver exploring the wreck of the Italian tugboat Ursus which sank on 31 January 1941, covered with yellow sponges (Aplysina cavernicola), near Stoncica lighthouse, Vis Island, Croatia, Adri...

Claudio Contreras / Yellow tube sponge (Aplysina fistularis) and diver, Guanahacabibes Peninsula National Park, Pinar del Rio Province, western Cuba., Floating debris cleaned

Franco Banfi / Propeller blade covered with yellow sponges, (Aplysina cavernicola) on wreck Vassilios T, Vis Island, Croatia, Adriatic Sea, Mediterranean

Alex Mustard / Coral reef scene, with Philippines chromis (Chromis scotochiloptera), hard coral (Acropora sp.) and purple elephant ear sponges (Ianthella basta). Apo Island Marine Protected Area, Dumaguete, Negros,...