Courtesy of Susi von Oettingen, USFWS / Flickr Creative Commons

Courtesy of Gary Peeples, USFWS / Flickr Creative Commons

Courtesy of Roger Tabor, USFWS / Flickr Creative Commons

Courtesy of Natural England, Michael Hammett / Flickr Creative Commons

Courtesy of Eyeweed / Flickr Creative Commons

Courtesy of Suzanne Cadwell / Flickr Creative Commons

Courtesy of Freshwater Biological Association

Courtesy of I, Boldie / Wikimedia Creative Commons