I dont think that it is a warmouth, i have one in a 75 gal 10' from me. the mouth is to small, color on the body is wrong as well. When my warmouth gets real stressed it can range from dark purple to almost a camo pattern to a pale silver green, but the markings on your fish remind me more of a longear or pumpkin seed. the face markings are peculiar though.
it just looks nothing like my warmouth
that fish is strange looking,