Andy Rouse / Great crested grebe (Podiceps cristatus cristatus) courtship weed dance, Cardiff, UK, March.

Andy Rouse / Great crested grebe (Podiceps cristatus cristatus) courtship dance at dawn, Cardiff, UK, March.

Nick Upton / Mute swan (Cygnus olor) female and a young cygnet foraging in sunset light, Kennet and Avon canal, Caen Hill, Wiltshire, UK, June.

Linda Pitkin / 2020VISION / River Itchen, with aquatic plants reflected in the surface. Blunt-fruited Water-starwort (Callitriche obtusangula). Ovington, Hampshire, England, May.

Linda Pitkin / 2020VISION / Split level view of the River Itchen, with aquatic plants: Blunt-fruited Water-starwort (Callitriche obtusangula). Itchen Stoke Mill is visible on the left. Ovington, Hampshire, England, May.

Linda Pitkin / 2020VISION / Aquatic plants in River Itchen: Blunt-fruited Water-starwort (Callitriche obtusangula), and Stream Water-crowfoot (Ranunculus penicillatus subsp. pseudofluitans). Ovington, Hampshire, England, May.

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

Pete Oxford / Butterfly peacock bass (Cichla ocellaris) in permanent freshwater pond, savannah, Rupununi, Guyana

Fabio Liverani / Crested Newt (Triturus cristatus carnifex) underwater view of female swimming near surface, Traversari lake, Campigna National Park, Emilia Romagna and Tuscany regions, Italy

Marie Read / Clark's grebes (Aechmophorus clarkii) courting pair performing the 'Weed Ceremony' in which they slowly circle breast to breast holding pond weed as nesting material, Lake Hodges, Escondid...

Claudio Contreras / Morelet's crocodile (Crocodylus moreletii), captive Catemaco Lake, Los Tuxtlas Biosphere Reserve, Mexico, July

Claudio Contreras / Morelet's crocodile (Crocodylus moreletii) close up of eye under pond weed, captive Catemaco Lake, Los Tuxtlas Biosphere Reserve, Mexico, July