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

Nick Upton / European eel (Anguilla anguilla) elver migrating upstream, using an eel pass on the side of a weir, Somerset Levels, England, UK, July.

Dave Bevan / Male Blackbird (Turdus merula) catching European eel (Anguilla anguilla) elvers as they migrate up a waterfall, Ceredigion, Wales, UK, July.

Dave Bevan / Male Blackbird (Turdus merula) catching European eel (Anguilla anguilla) elvers as they migrate up a waterfall, Ceredigion, Wales, UK, July.

Dave Bevan / European eel (Anguilla anguilla) elvers migrating up a wet rock next to a waterfall, Ceredigion, Wales, UK, July.

David Fleetham / Pair of Yellow edged moray eels (Gymnothorax flavimarginatus) in coral crevice, Hawaii.

Alex Mustard,Alex Mustard / Portrait of a Yellow moray eel (Gymnothorax prasinus) - endemic to SE Australia. Chowder Bay, Sydney Harbour, New South Wales, Australia.

Juergen Freund / Yellow ribbon eel / Ribbon moray eel (Rhinomuraena quaesita). Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Yellow ribbon eel / Ribbon moray eel (Rhinomuraena quaesita). Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Blue ribbon eel / Ribbon moray eel (Rhinomuraena quaesita). Lembeh Strait, North Sulawesi, Indonesia.

Brent Hedges / Yellow edged moray eel {Gymnothorax flavimarginatus} with cleaner wrasse. Milne Bay, Australia

Chris Newbert / Scarlet Cleaner Shrimp (Lysmata amboinensis) pair cleaning a Moray Eel (Gymnothorax ocellatus) 80 feet deep, Solomon Islands