4" - 5".
So,, how large will YP get?
That's good growth. If your perch are like mine the females will get into the 14 inch range with a few around 15 inches or slightly over. Contrary to all the fish stories out there (which they never seem to have the camera) it's very rare for a yellow perch to reach 16 inches or over. I've only had one do that. Never mounted one that big in the 30 plus years I've been doing taxidermy either.
Here's my only 16 incher (16 1/4) at 2 lbs.13 oz. (2.81lbs.) Apparently an anomaly. I caught her ice fishing in February. She may have gone 3 lbs. if I would have caught her when her eggs were at maximum size a month or too later.
