This goldfish (Carassius auratus) has got to be one of the more unusual creatures we have come across. We’re not sure what caused this abnormal distension of the abdominal cavity, but we were definitely surprised when it was captured in a Sierra Nevada reservoir.
Thought to be the first non-native freshwater fish species introduced to North America, goldfish were intentionally released in the 1800’s. Early settlers likely intentionally released them as an ornamental fish rather than as a game fish. Now they are established or reported in all states except Alaska.
Photo source: FISHBIO