Morley Read / Aerial shot ascending over rainforest canopy at dawn, with the Rio Napo in background, a tributary of the Amazon, Napo Province, Ecuador, 2017. (non-ex)

Michel Roggo / Perch (Perca fluviatilis). Juktan river, tributary of Umeälven river, Lapland, Sweden, July.

Rob Jordan / 2020VISION / Tributary of the River Tweed where Brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) come to spawn, Cheviot Hills, Northumberland, England, UK, October

Florian Möllers / Polluted tributary of the Li River with town and mountains on the horizon. Yangshuo, Guangxi, China, November 2006.

Graham Eaton / A shoal of Minnows (Phoxinus phoxinus) in a quiet tributary of the River Glaslyn. Porthmadog, Wales, July.

Nick Garbutt / Wild female Jaguar (Panthera onca palustris) jumping up sandy bluff on the banks of the Piquiri River (a tributary of Cuiaba River). Northern Pantanal, Brazil. September

Nick Garbutt / Wild female Jaguar (Panthera onca palustris) resting on the banks of the Piquiri River (a tributary of Cuiaba River). Northern Pantanal, Brazil.

Nick Garbutt / Wild Ocelot (Felis pardalis) on the banks of the Piquiri River (a tributary of Cuiaba River) Northern Pantanal, Brazil. September

Jerry Monkman / Roaring Brook, a tributary of Batten Kill river, in the Green Mountain National Forest, Sunderland, Vermont, USA, October 2009

Kevin Schafer / Split level view of Amazon River Dolphin / Boto (Inia geoffrensis) in flooded forest, Ariau River, tributary of Rio Negro, Amazonia, Brazil, July

Michel Roggo / Three-barred / speckled peacock bass (Cichla temensis) entering flooded forest to spawn. Tributary Rio Tabajos, Para, Brazil.

Michel Roggo / Underwater landscape in Spring creek, Saane river tributary, in winter, Gruyre, Fribourg, Switzerland. February