doesn't matter if it had sea lice or not. if it was in the saltwater it will have the lice.A couple ways to tell blackmouth from kings are the scales don't come off easily on a king like they do on a bm, they are "set". Also when you clean it the bm will be VERY sexually immature, like eggs would look trout sized, an adult, even a springer would have bigger eggs,(or milt sacs if a male). I also notice bm smell different than adults but that is pretty hard to describe on the computer.