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 / 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 / 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

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

Doug Perrine / Yellow tube sponge {Aplysina fistularis} with Yellowtail snappers {Ocyurus chrysurus Cayman Brac, Cayman Islands, Caribbean

Doug Perrine / Diver looking at Purple tube sponge {Aplysina lacunosa} Bahamas, Caribbean

Doug Perrine / Bottlenose dolphin {Tursiops truncatus} Cayman Islands, Caribbean Sea (Non-ex).

Doug Perrine / Bottlenose dolphin {Tursiops truncatus} Cayman Islands, Caribbean Sea (Non-ex).

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

David Fleetham / Blue spiral fan (used for feeding and breathing) of Christmas tree worm (Spirobranchus giganteus) visible on reef. Maui, Hawaii.

David Fleetham / Caribbean trumpetfish (Aulostomus maculatus) camouflaged among Tube sponges (Aplysina sp). Bonaire, Netherlands Antilles, Caribbean.

Alex Mustard / Colourful coral reef wall, with yellow branching tube sponges (Pseudoceratina crassa), brown tube sponges (Agelas conifera) and red rope sponges (Amphimedon compressa), in front of deepwater sea fans...

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

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...

Michael Pitts / Tube or trumpet sponges (Aplysina fistularis?) Tobago. Caribbean

Alex Mustard / Diver photographing a large formation of yellow tube sponges (Aplysina fistularis) growing on a coral reef, North Wall, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea. Model released...

Alex Mustard / Brown tube sponges (Agelas conifera) formation on reef wall with diver above, image taken with a circular fisheye, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Brown tube sponges (Agelas conifera) formation on reef wall, with diver in distance, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Brown tube sponges (Agelas conifera) formation on a reef wall, with sun shining through the water and diver above, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Brown tube sponges (Agelas conifera) and deepwater sea fans (Iciligorgia nodulifera) with a diver in background exploring the reef, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbe...

Alex Mustard / Yellow tube sponge (Aplysina fistularis) selectively illuminated with a diver swimming above, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Yellow tube sponge (Aplysina fistularis) on a coral reef, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Coral reef outcrop with brown tube sponges (Agelas conifera) deepwater sea fans (Iciligorgia nodulifera) and knobby cactus coral (Mycetophyllia aliciae) East End, Grand Cayman, Cayman Islands, Britis...

Pete Oxford / Yellow tube sponge (Aplysina fistularis) on coral reef, Coral Reef Island, Belize Barrier Reef, Belize

Pete Oxford / Stove-pipe Sponge (Aplysina archeri) on coral reef, Coral Reef Island, Belize Barrier Reef, Belize

Pete Oxford / Yellow tube sponge (Aplysina fistularis) on coral reef, Coral Reef Island, Belize Barrier Reef, Belize

Georgette Douwma / Tube Sponge (Callyspongia sp.) with crinoids on coral reef. Rinca, Komodo National Park, Indonesia.

Sue Daly / Painted Frogfish (Antennarius pictus) camouflaged amongst tube sponge on coral reef, Cebu, Philippines, March

Sue Daly / Painted Frogfish (Antennarius pictus) camouflaged amongst tube sponge on coral reef, Cebu, Philippines, March

Tim Laman / Brittlestars {Ophiuroidea} on tube sponge amongst mangrove roots, Tunicate Cove, Belize.

Doug Perrine / Caribbean trumpetfish, Caribbean {Aulostomus maculatus} hiding amongst tube sponge {Aplysina fistularis} Dominica, Caribbean

Juergen Freund / Tube sponge {Verongia aerophoba} Mediterranean Sea

Juergen Freund / Yellow tube sponge {Aplysina fistularis} growing on shipwreck, with diver in background, Caribbean

Juergen Freund / Brown tube sponge {Agelas wiedenmayeri} Caribbean

Constantinos Petrinos / Orange cup coral {Tubastrea coccinea} and Tube sponge, Bonaire, Caribbean

Juergen Freund / Yellow tube sponge and diver (Aplysina fistularis) Caribbean

Juergen Freund / Yellow tube sponge (Aplysina fistularis) Caribbean

Doug Perrine / Yellow grouper {Epinephelus fulvus} and purple tube sponges on wreck of The Rhone, British Virgin Is, Caribbean

Jurgen Freund / Diver swimming over Yellow tube sponge (Aplysina fistularis) Caribbean

Doug Perrine / Social feather duster worms {Bispira brunnea} and red encrusting sponge {Monanchora barbadensis} St Vincent, Caribbean

Doug Perrine / Yellow tube sponge {Aplysina fistularis} and Sea fan coral {Gorgonia ventalina} Cayman Islands, Caribbean

Juergen Freund / Tube sponge (Porifera sp) on coral reef, Cuba, Carribean

Juergen Freund / Yellow tube sponge (Porifera sp) Cuba, Caribbean

Juergen Freund / Yellow tube sponge and diver (Aplysina fistularis) Caribbean

Constantinos Petrinos / Orange Cup corals {Tubastrea coccinea} & Tube sponge. Bonaire, Caribbean

Doug Perrine / Bottle nosed dolphin {Tursiops truncatus} Cayman Islands, Caribbean Sea (Non-ex).

Juergen Freund / Diver and Yellow tube sponge (Aplysina fistularis) growing on ship wreck

Angelo Giampiccolo / Colony of Brittle stars (Ophiurida) on tube sponges, Belize Cayes, Caribbean.

Angelo Giampiccolo / Colony of tube sponges, with a sea fan (left) and some fire coral. Belize Cayes, Caribbean.

Angelo Giampiccolo / Colony of Brittle stars (Ophiurida) on tube sponges, in the Belize Cayes, Caribbean.

Angelo Giampiccolo / Tube sponges (Aplysina sp) Belize Cayes, Caribbean.

Roberto Rinaldi / Giant tube sponge (Aplysina genus) and sea fans, Cayman Islands.

Roberto Rinaldi / Coral reef with deep water sea fans, tube sponges and in the foreground a colony of lettuce coral, Honduras.

Roberto Rinaldi / Vase sponge, tube sponges, sea-plumes and sea whips, Honduras.

Roberto Rinaldi / Corals, sea fans and tube sponges, Honduras.

Roberto Rinaldi / Tube sponges (Agelas sp) on coral reef, Honduras.

Roberto Rinaldi / Diver and rope sponge (aplysia sp), Honduras.

Roberto Rinaldi / Yellow tube sponges (Aplysina fistularis), Belize.

Roberto Rinaldi / Gorgonian sea fans, Alcuonarian soft coral and Tube sponges. Tubbataha reef, Philippines.

Angelo Giampiccolo / Arrow crab (Stenorhynchus seticornis) on tube sponge at night, Belize Cayes, Caribbean.

Angelo Giampiccolo / Arrow crab (Stenorhynchus seticornis) in tube sponge at night, Belize Cayes, Caribbean.

Angelo Giampiccolo / Arrow crab (Stenorhynchus seticornis) on a tube sponge at night, Belize Cayes, Caribbean.

Angelo Giampiccolo / Arrow crab (Stenorhynchus setircornis) on tube sponge, at night in the Belize Cayos, Caribbean.