The bars on the back half of that YP are definitely NOT vertical. Is that due to its rapid growth? Is that a sex differentiation? Is that something particular to your strain of YP? Or are their vertical bars of YP somewhat random in orientation?
It is normal in my experience to see variation of pattern of the vertical bars on yellow perch in every population. The variation seems to me to be genetically affiliated. I get numerous YP with one or a few of the bars in the shape of Y. This pattern equates to the pattern of different stripes on the skin of most fish that have stripes.
The YP pictured above in just the beginning of big perch that will be produced by Snipe. Expect siblings of that YP in 1-2 years to be close to or at 16". Thereafter their diet will determine how much longer they live and grow toward the elusive 17"-19" YP. The state record YP in Michigan is 21".
