Although freshwater environments, from creeks to rivers, brim with more than 10,000 species of fish, we may never get the chance to see many of these mysterious creatures as their populations decline.

For years, Heinz Machacek has kept records of big freshwater fish on his website. ... A vintage 1911 photo of a 105-pound Murray Cod from Australia. (Photo/Heinz Machacek) Record Weight: 105 pounds.

Tons of dead fish fill a river near Volos, Greece, Aug. 29. (Vaggelis Kousioras/AP) A mass cleanup effort is underway in Greece after more than 100 tons of dead freshwater fish were discovered ...

This bluegill collected during the study contained 16,973 Haplorchis pumilio and 8 Centrocestus formosanus infectious trematode parasite larval stages. Photo: Emma Palmer. The study identified two ...

More than 90% of popular freshwater fish in Southern California are carrying human-infecting parasites, researchers say. This poses a significant danger for those who like to eat freshly caught ...

America's freshwater rivers and lakes are losing their secret weapon: freshwater mussels. As an invaluable part of nature’s clean-up crew, their absence could have a nasty knock-on effect on ...

(Photo provided by the Alaska Department of Fish and Game) Northern pike are native to much of the state, a fixture in freshwater systems north of the Alaska Range.