Bryan and Cherry Alexander / Rainbow over a Khanty reindeer herders' camp by the Bolshaia Paipudyna River in the Polar Urals Mountains. Yamal, Western Siberia, Russia, Summer 2007.

Michel Roggo / Rainbow trout (Salmo gairdneri / Oncorhynchus mykiss) Sava river, Slovenia, 2005

Michel Roggo / Rainbow trout (Salmo gairdneri / Oncorhynchus mykiss) in pool of the Lepena river, Slovenia 2006

Michel Roggo / Rainbow trout (Salmo gairdneri / Oncorhynchus mykiss) in pool of the Lepena river, Slovenia 2006

Barry Bland / Rainbow Trout {Salmo gairdneri} Fly Fishing on the Clutha River, Wanaka, New Zealand. Model Released.

Norbert Wu / Iguacu Falls, world's largest waterfalls, Brazil and Argentina border

Pete Oxford / Rainbow over Madre de Dios River, Peru.

Gavin Hellier / Skogafoss Falls, one of 20 waterfalls found along the Skogar River, with rainbow in spray, Skogar, Southern Iceland 2006

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Rainbow Trout (Oncorhynchus mykiss), on spawning ground. Male approaching female to spawn. Lichtensteiner Binnenkanal, tributary of the Rhine River, Lichtenstein, January.

Michel Roggo / Dead Rainbow trout (Oncorhynchus mykiss). Tolminka river, tributary of the Soca river, Julian alps, Slovenia, September.

Michel Roggo / Dead Rainbow trout (Oncorhynchus mykiss). Tolminka river, tributary of the Soca river, Julian alps, Slovenia, September.

Richard Herrmann / Rainbow Trout (Oncorhynchus mykiss) and juvenile, these anadromous steelhead are locally endangered, Big Sur River, California

Paul D Stewart / Lower Yellowstone Falls, Yellowstone river. These 33 meter high falls are the largest volume falls in the Rocky Mountains of the USA. The yellow rock around the river is a thermally degraded (hydrothe...

Linda Pitkin / 2020VISION / Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) in disused quarry, Jackdaw Quarry, Capernwray, Carnforth, Lancashire, UK, August

Bryan and Cherry Alexander / Rainbow over a Khanty reindeer herders' camp by the Bolshaia Paipudyna River in the Polar Urals Mountains. Yamal, Western Siberia, Russia, Summer 2007.

Guy Edwardes / View of Gullfoss / Golden Falls with rainbow, Hvita River, Iceland. October 2009

Michel Roggo / Rainbow trout (Salmo gairdneri / Oncorhynchus mykiss) Idrijca river, Slovenia, 2005

Inaki Relanzon / Rainbow in spray from the Gullfoss waterfall in the river Hvita, South of Langjokull glacier, SW Iceland. July 2008

Tim Laman / Full rainbow arch over Red mangrove forest {Rhizophora mangle} and river channel in Caroni Swamp. Caroni Bird Sanctuary, Trinidad, Trinidad and Tobago. February 2006

Kirkendall-Spring / Rainbow at the base of Vernal Falls on the Merced River, Yosemite National Park, California, USA

Jerry Monkman / Rainbow set against mountains of the Alaska Range near the Toklat River, Denali National Park, Alaska, USA

Jerry Monkman / Rainbow set against mountains of the Alaska Range near the Toklat River, Denali National Park, Alaska, USA

Konrad Wothe / Rainbow over Namorona River, Ranomafana National Park, Madagascar

DAVID TIPLING / Oak woods and rainbow over river at Dinas and Gwenffrwd RSPB reserve, Dyfed, Wales

DAVID TIPLING / Oak woods and rainbow over river at Dinas and Gwenffrwd RSPB reserve, Dyfed, Wales

Adam White / Rainbow River, Rainbow Springs State Park, Florida, USA

Adam White / Canoeist on Rainbow River, Rainbow Springs State Park, Florida, USA

Adam White / Rainbow River, Rainbow Springs State Park, Florida, USA

Adam White / Rainbow River, Rainbow Springs State Park, Florida, USA

Adam White / Rainbow River, Rainbow Springs State Park, Florida, USA

Adam White / Peole canoeing on Rainbow River, Rainbow Springs State Park, Florida, USA

Gabriel Rojo / Iguazu falls and rainbow, Iguazu NP, Argentina / Brazil

Gerry Ellis / Hippopotamus (Hippopotamus amphibius) group soaking in Linyanti River, with rainbow in the background, Moremi Wildlife Reserve, Botswana

Michael & Patricia Fogden / Iguacu falls as seen from the Brazilian side, Brazil and Argentina border

Michael Quinton / Rainbow Trout (Oncorhynchus mykiss) group underwater in the summer, Henry's Fork of the Snake River, Idaho

Martin Gabriel / River Tsauchab after heavy rains with rainbow Sesriem, Namibia

Rob Jordan / 2020VISION / Panoramic view over the River Tweed at sunrise of the Eildon Hills from 'Scott's View', with rainbow, Melrose, Scotland, England, UK, May

Rob Jordan / 2020VISION / Panoramic view over the River Tweed of the Eildon Hills from 'Scott's View', with rainbow, Melrose, Scotland, England, UK, May

Barry Bland / Drift fishing for rainbow trout (Oncorhynchus mykiss), Clutha River, Wanaka, New Zealand.

Barry Bland / Drift fishing for rainbow trout (Oncorhynchus mykiss), Clutha River, Wanaka, New Zealand.

Barry Bland / Drift fishing for rainbow trout (Oncorhynchus mykiss), Clutha River, Wanaka, New Zealand.

Kirkendall-Spring / Rainbow over the Quinault River Valley in Olympic National Park. Washington, USA, September 2009

Flip de Nooyer / Kaieteur Waterfall on the Potaro River, highest waterfall, Guyana

Norbert Wu / Iguacu Falls, world's largest waterfalls Brazil and Argentina border