Lycoptera were small freshwater fish that lived during the Early Cretaceous, approximately 125-113 million years ago, in China, North Korea, Mongolia, and Siberia. Most species fed on plankton, had numerous tiny teeth, and were covered with tiny oval scales, approximately 1.2 millimeters in diameter. Many fossilized specimens preserve details and impressions of soft tissues. Lycoptera specimens are commonly found fossilized in large groups that were buried together rapidly in fine lake sediments, likely due to mass mortality events caused by the upwelling of anoxic waters during late autumn and winter. This suggests that they were gregarious animals, gathering in large shoals.
