Lots of lakes have private companies stock "lunkers" just like that. You will never find it written anywhere lol. I have caught 3 of the 4 stocked kinds ...more of trout (brook,brown,rainbow) and have seen but never caught the 4th (palomino), in the stream behind my house. The state website says they only stock browns lol. I'd say that makes it an even better catch!
Not sure of the lakes name, it's at the end of shades of death trail. Caught it on the campground side back in the shallow corner behind the pine trees