Alex Mustard / Saddleback anemonefish (Amphiprion polymnus) barks a warning as it guards a clutch of developing eggs (beneath it) laid on a small stone, below a fold in its home, a Haddon's sea anemone (Stichoda...

Shane Gross / Pink anemonefish (Amphiprion perideraion) living in symbiotic association with Magnificent sea anemone (Heteractis magnifica) Palau.

Shane Gross / Pink anemonefish (Amphiprion perideraion) living in symbiotic association with Magnificent sea anemone (Heteractis magnifica), Palau

Shane Gross / Clark's Anemonefish (Amphiprion clarkii) tending to her eggs. Kimbe Bay, Papua New Guinea

Alex Mustard / Western clown anemonefish (Amphiprion ocellaris) poses with a large, dominant female behind. The clownfish in the foreground is probably a juvenile. Bitung, North Sulawesi, Indonesia. Lembeh Strait, M...

Fred Olivier / Orange clownfish (Amphiprion percula) living in association with a Haddon's sea anemone (Stichodactyla haddoni), Marovo Lagoon, Solomon Islands.

Fred Olivier / Clark's anemonefish (Amphiprion clarkii) and Three spot damselfish (Dascyllus trimaculatus) swimming around anemone (Stichodactyla), Nusatupe Lagoon, Solomon Islands.

Alex Mustard / Three Pink anemonefish (Amphiprion perideraion) living in a purple skirted magnificent sea anemone (Heteractis magnifica) on a coral reef, below a small island. Misool, Raja Ampat, West Papua, Indones...

Alex Mustard / Pair of Western clown anemonefish (Amphiprion ocellaris) spawning orange eggs on the rock beneath their Magnificent sea anemone (Heteractis magnifica) home on a coral reef. This photo shows the larger...

Pascal Kobeh / False clown anemonefish (Amphiprion ocellaris) in a magnificent sea anemone (Heteractis magnifica), Sulu sea, Philippines

Denis-Huot / Clownfish (Amphiprion sp) in anemone home, Philippines.

Nick Hawkins / Sergeant major (Abudefduf sp) schooling in mangroves of Isabela Island, Galapagos.

Jurgen Freund / Shoal of Sergeant majors (Abudefduf saxatilis) with various Wrasses (Labridae) feeding on the Sergeant major fish eggs, Raja Ampat, Indonesia.

David Fleetham / Clark's anemonefish (Amphiprion clarkii), pair tending to egg mass placed beside the protection of an anemone. Yap, Micronesia.

Alex Mustard / Schools of Pacific creolefish (Cephalopholis colonus) and Panamic sergeant major (Abudefduf troschelii) swimming through sun beams inside an underwater cavern. Los Islotes, La Paz, Baja California Sur...

Franco Banfi / Three False clownfish (Amphiprion ocellaris) in Sea anemone (Heteractis magnifica) Lighthouse Reef, Cabilao Island, Bohol, Central Visayas, Philippines, Pacific Ocean.

Jordi Chias / Red Sea anemonefish (Amphiprion bicinctus) in their home, a Sea anemone (Heteractis magnifica), on a coral reef. Big Brother island, Red Sea. Egypt.

Brandon Cole / Pink anemonefish (Amphiprion perideraion) lives in symbiotic association with Magnificent sea anemone (Heteractis magnifica) Great Barrier Reef, Australia, Pacific Ocean

Alex Mustard / Maldive anemonefish (Amphiprion nigripes) shoal swimming in the current flowing over a Magnificent sea anemone (Heteractis magnifica). Baa Atoll, Maldives. Indian Ocean.

Alex Mustard / Maldivian anemonefish (Amphiprion nigripes) shelters against a closed magnificent sea anemone (Heteractis magnifica). Male Atoll, Maldives. Indian Ocean.

Alex Mustard / Red and black anemonefish (Amphiprion melanopus) in a Bulb tentacle sea anemone (Entacmaea quadricolor). Kri Island, Raja Ampat, West Papua, Indonesia, South East Asia. Dampier Strait, Tropical West P...

Alex Mustard / Scissortail sergeants (Abudefduf sexfasciatus) swimming over hard corals (Acropora sp.) on shallow reef at sunset, split level view. Gubal Island, Egypt. Red Sea.

Alex Mustard / Saddleback anemonefish (Amphiprion polymnus) in anemone home, Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Doug Perrine / Barjacks (Caranx ruber), Yellowtail snapper (Ocyurus chrysurus), and Sergeant major damselfish (Abudefduf saxatilis) swimming around wreck of bow gun on C-58 shipwreck off Puerto Morelos, near Cancun,...

Alex Mustard / Pink anemonefish (Amphiprion perideraion) looks out from its host Magnificent sea anemone (Heteractis magnifica) Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocea...

Alex Mustard / Portrait of Red Sea anemonefish (Amphiprion bicinctus) against open water. Abu Nuhas, Strait of Subal, Egypt. Gulf of Suez, Red Sea.

Alex Mustard / RF- Pair of Red Sea anemonefish (Amphiprion bicinctus) in Magnificent sea anemone (Heteractis magnifica), which has closed up in the late afternoon revealing its red skirt. St Johns Reef. Egypt. Red S...

Alex Mustard / Red Sea anemonefish (Amphiprion bicinctus) in Magnificent sea anemone (Heteractis magnifica), which has closed up in the late afternoon, on coral reef under stormy seas. St Johns Reef. Egypt. Red Sea.

Alex Mustard / Red Sea anemonefish (Amphiprion bicinctus) in front of magnificent sea anemone. Anemone City, Ras Mohammed Marine Park, Sinai, Egypt. Gulf of Aqaba, Red Sea.

Michael Pitts / Maldives clownfish (Amphiprion nigripes) chasing juveniles, with anemones (Actiniaria) in the background, Maldives, Indian Ocean.

Michael Pitts / Anemones (Actiniaria) with Maldives anemonefish (Amphiprion nigripes) and Surgeonfish (Acanthurus) moving in a strong current, Maldives, Indian Ocean.

Michael Pitts / Maldives anemonefish (Amphiprion nigripes) and Surgeonfish (Acanthurus) swimming in a strong current, with moving anemones (Actiniaria), Maldives, Indian Ocean.

Michael Pitts / Maldives anemonefish (Amphiprion nigripes) and Surgeonfish (Acanthurus) swimming in a strong current, with moving anemones (Actiniaria), Maldives, Indian Ocean.

Claudio Contreras,Claudio Contreras / Black-axil Chromis (Chromis atripectoralis) blurred motion photograph. Bilang Bilangang Island, Danajon Bank, Central Visayas, Philippines, April

Magnus Lundgren / Wild Wonders of China / Ocellaris clownfish (Amphiprion ocellaris) Green Island, Taiwan.

Magnus Lundgren / Wild Wonders of China / Ocellaris clownfish (Amphiprion ocellaris) Green Island, Taiwan.

Magnus Lundgren / Wild Wonders of China / Pink anemone fish (Amphiprion perideraion) at host anemone, Green Island, Taiwan.

Magnus Lundgren / Wild Wonders of China / Tomato clownfish (Amphiprion frenatus) Green Island, Taiwan.

David Fleetham / Bridled anemonefish (Amphiprion frenatus) in a Bulb-tenacle sea anemone (Entacmaea quadricolor) in reef of finger coral, Yap, Micronesia.

Pascal Kobeh / Blue chromis (Chromis cyanea) with attached parasitic Isopod (Anilocra sp) female feeding on blood, in reef. Bahamas.

Pascal Kobeh / Blue chromis (Chromis cyanea) with parasitic Isopod (Anilocra sp) female feeding on blood. Male isopods invisible to naked eye, female excretes a chemical substance to maintain masculinity of small ma...

Claudio Contreras / Threespot damselfish (Stegastes planifrons) juvenile, Cozumel Island, Caribbean Sea, Mexico.

Claudio Contreras / Threespot damselfish (Stegastes planifrons), Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico.

Claudio Contreras / Yellowtail damselfish (Microspathodon chrysurus) juvenile, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico, May

Claudio Contreras / Dusky damselfish ( Stegastes adustus ), Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico.

Claudio Contreras / Dusky damselfish ( Stegastes adustus ), Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico.

Claudio Contreras / Threespot Damselfish (Stegastes planifrons) juvenile, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico, May

Claudio Contreras / Sergeant Major (Abudefduf saxatilis), Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico, May