Blue Mouth Pike

Tonight I caught a small (about 18 inch) pike fishing a small river in southern Wisconsin. I immediately noticed a bluish mouth and fins. The mouth is definitely more noticeable than the fins. I took a some pics, than sent her back wondering what the deal with that. I figured maybe it was due to chemicals in the water way. 

After doing some research it appears that it was a fairly rare fish with possibly a genetic difference. Other researcher shows that it can be common in spring northern when the water is cold. Well it’s August and the water isn’t cold. 

I am curious if anyone else has caught a pike like this and any opinion on this subject. Maybe it’s not as rare as the research says. Who knows?  Thank you!

Witnessed  a small pike, around 20", caught yesterday 1-8-2023 while tip-up fishing on Lake Mendota, Madison.

Looked perfectly healthy otherwise.  Mainly the mouth and tail had the blue coloring. 

I caught a pike similar to the one pictured in the article Paul A. Smith article when I was fishing in a Southeastern Wisconsin Creek.  I always thought it was kinda weird, but I let it go as I was in the middle of a kayak fishing trip.  You can see the pike with some blue tint in its mouth at around the four minute mark of this fishing trip.