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

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Yellow-edged Moray (Gymnothorax flavimarginatus), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Honeycomb Moray Eel (Gymnothorax favagineus), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Goldbelly Cardinalfish (Apogon apogonides), Tulamben, Bali, Indonesia

Nigel Cattlin / Symptoms of Neck blast (Magnaporthe grisea) on Rice (Oryza sativa) plants in ear, Luzon, Philippines

John Chan / Elegant tern (Thalasseus elegans) with a broken wing, attempting to take off, Southern California, USA, April.

John Chan / Western gulls (Larus occidentalis) attacking an Elegant tern (Thalasseus elegans) with a broken wing, Southern California, USA, April.

Sven Zacek / Bearded seal (Erignathus barbatus) sunbathing on iceberg broken off from glacier. Kongsfjorden fjord, Spitsbergen, Norway. June 2014.

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

Alan Murphy/ BIA / Killdeer (Charadrius vociferus) in broken wing display, Texas