Solvin Zankl / Lars Hendrickson watching Black piston water beetles (Hydrophilus aterrimus) feeding on a tadpole, State Collection in Munich, Germany, June

Alex Mustard / A captive Zebra shark (Stegostoma fasciatum / varium) portrait, with diver behind, in Brighton Sealife Centre, Brighton, England, UK. Model released, not property released

Neil Lucas / Sea nettles (Chrysaora quinquecirrha) in aquarium, with crowd of people watching, Atlanta, USA, October 2009

Jeff Rotman / Japanese Giant Spider Crab (Macrocheira kaempferi) World's Largest Crustacean in Tokyo Aquarium, Japan.

Philippe Clement / School of Pollack fish (Pollachius pollachius), North Sea, Europe, Captive

Hiroya Minakuchi / Beluga (Delphinapterus leucas) whale trio blowing toroidal bubble rings, play behavior, vulnerable, Shimane Aquarium, Japan

Hiroya Minakuchi / Beluga (Delphinapterus leucas) whale trio calling, vulnerable, Shimane Aquarium, Japan

Flip Nicklin / Beluga (Delphinapterus leucas) whale portrait in aquarium

Juergen Freund / Aquarium trade fisherman on huka. Paint compressor supplies air to the fishermen who can stay underwater long to catch ornamental fish. Verde Island, Mindoro, Philippines

Juergen Freund / Aquarium fish caught in an accredited manner without using cyanide but with a net. Fish handlers put compressed air into assorted ornamental, tropical fish. Verde island, Mindoro, Philippines

Juergen Freund / Aquarium fish caught in an accredited manner without using cyanide but with a net. Fish handlers put compressed air into assorted ornamental, tropical fish. Verde island, Mindoro, Philippines

Doug Perrine / False killer whale ( Pseudorca crassidens ) with mouth open, showing large conical teeth, captive, aquarium, from Indo-pacific, digitally manipulated