Fossil Fish – Knightia species

Knightia are the most common fish in the Green River Formation, an Eocene geologic formation in the Rocky Mountains, also known as the Fossil Lake. Fish found in the limestone from this region are very common and quite well preserved, probably a result of sudden falls of ash from volcanic activity.

Knightia were a main component of the diets of larger fish, like Diplomystus, another very common fish in the formation. Knightia themselves were secondary consumers, feeding mainly on algae and plankton.

These limestone fossils vary in color depending on the layer of stone they were found in. They range from light brown to almost black, with the lighter brown ones often showing greater detail.