With sunfish it's difficult to be certain because so much hybridization goes on. And this one in particular has some funky markings/bars and then they're nonexistent. It has all the criteria to be a Redear Sunfish. Or at least it's half Redear. Besides the red tick, it has the shape of a Redear and the long pointy pec fin unique to only a couple of sunfish species. It could very well be a pure Redear. Spawning young male too (note blue worm markings in cheek). Redears (like Smallies) can have bars or be solid "yellowish/gold". Or they can also have a pretty, tight checkerboard-like pattern with numerous colors within the pattern. Again, this one is unique/odd because it hasn't decided which coloration it wants to be - ha! Looks like a teenager and that may be why it's in-between colors. Many fish start out much differently than they end up looking as adults. And Redears have one of the biggest ranges of different color possibilities of any Sunfish IMO. I don't see any Warmouth in it, but like I said with sunfish it's not always easy to tell with hybrids.