Dorado

The dorado is a fish you catch in rivers. Look for a very large shadow. In the northern hemisphere look for it in Jun – Sep, from 4 AM – 9 PM. It can only appear after you have caught 100 fish. Nook's Cranny pays 15,000 Bells, C.J. pays 22,500 Bells.

An X-Large river shadow out from 4am to 9pm once you have 100 catches. It sells for 15,000 Bells, and fishing the rivers on mystery islands gives you extra chances.