Northern studfish are a type of fish.
Like all types of fish, each northern studfish gives one fish fillet when caught.
Catching northern studfish
Northern studfish can be caught with green and blue lures in any fishing spot, but their favorite spot is #8 (the rocky area near the fishing boat).
Northern studfish can be caught in medium circles and therefore are a bit harder to catch.
See Fishing List for more detailed information.
Northern studfish in the fishing book
The northern studfish is on page 15 of the fishing book:
Small but feisty. If he bites, get ready for a fight!