David Shale / Female Anglerfish fanfin seadevil (Caulophryne jordani) - Deep sea species from Atlantic Ocean, found at 700-3000m.

Alex Mustard / Whale shark (Rhincodon typus) close to the camera with a golden trevally fish (Gnathanodon speciosus) and outline of another whale shark behind , in the plankton-rich green waters of La Paz bay, Baja...

Alex Mustard / Orange painted frogfish (Antennarius pictus) fishing. Here the frogfish is illuminated by a snooted strobe and the background sand lit with a red LED torch. Bitung, North Sulawesi, Indonesia. Lembeh S...

Tony Wu / View down the throat of a male Zoarchias major eelpout (Zoarchias major) that has opened its mouth during a confrontation with another male. Yamaguchi Prefecture, Japan. Pacific Ocean.

Tony Wu / Two male Zoarchias major eelpouts (Zoarchias major) engaged in a mouth-to-mouth confrontation. Yamaguchi Prefecture, Japan, Pacific Ocean.

Tony Wu / Zoarchias major eelpout (Zoarchias major) with her mouth wide open. Yamaguchi Prefecture, Japan, Pacific Ocean.

David Fleetham / Guineafowl pufferfish (Arothron meleagris) puffed up in defence, Hawaii.

Alex Mustard / Striped mackerel (Rastrelliger kanagurta) shoal swimming with open mouths, filtering for zooplankton. Marsa Shouna, Port Ghalib, Marsa Alam, Egypt. Red Sea

Alex Mustard / Striped mackerel (Rastrelliger kanagurta) mouth wide open as it swims through the water, filtering zoopankton with its gill rakers. Marsa Shouna, Port Ghalib, Marsa Alam, Egypt. Red Sea

Ingo Arndt / Sea trout (Salmo trutta trutta) alevin just hatched with full yolk sac, Europe

Alex Mustard / Warty / Clown frogfish (Antennarius maculatus) male portrait, Anilao, Batangas, Luzon, Philippines, March

Alex Hyde / Fishing spider (Trechalea) waiting to catch a Killifish (Cyprinodontiformes) in a rainforest stream at night, Central Caribbean foothills, Costa Rica.