RIVER NORTH — Last week, Ben Gorashchenko looked down into the Chicago River at the long, twisting, wriggling creature he just reeled in. Gorashchenko was pulling in an American eel — an extremely rare find in the Chicago River. Researchers told Block Club that, to their knowledge, there is just one other known instance of someone catching an American eel in the Chicago River in recent years, when a child caught one in 2017.