Gary Bell/ Oceanwide / Sea Goldie (Pseudanthias squamipinnis) school in coral reef with feather stars, Great Barrier Reef, Queensland, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Common Lionfish (Pterois volitans) hunting Basslets (Pseudanthias sp), Christmas Island, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning female Stocky Anthias (Pseudanthias hypselosoma), Tulamben, Bali, Indonesia

Shane Gross / Graysby fish (Cephalopholis cruentata) a type of grouper, hiding in a sponge off Eleuthera, Bahamas.

David Fleetham / Cleaner wrasse (Labroides dimidiatus) swimming alongside Golden damsel (Amblyglyphidodon aureus) looking for parasites, Fiji, Pacific Ocean.

Claudio Contreras / Black grouper (Mycteroperca bonaci) and Caribbean Reef Shark (Carcharhinus perezi), Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba, January

Jordi Chias / Potato cod (Epinephelus tukula) Zavora Coast, Mozambique, Indian Ocean.

Jordi Chias / Goliath grouper (Epinephelus itajara) inside a coral cave. Bloody Bay Wall, Little Cayman, Cayman Islands. British West Indies. Caribbean Sea.

Jordi Chias / Nassau grouper (Epinephelus striatus) on a coral reef, Little Cayman Island, Cayman Islands, Caribbean.

Jordi Chias / Two male Dusky groupers (Epinephelus marginatus) fighting for territory during mating season at 'baixa do meros', a small pinnacle at Formigas islets Protected area, near Santa Maria Island, Azores. F...