That's a kind of bullhead. I'm not sure what kind, but they keep the speckling even through maturity. I have one too. I saw a 15" one in the LFS where I got it with the speckled look just like yours.
Just caught this little guy earlier this morning. Im trying to catch a Pseed but didn't have any luck. This guy had some good looking colors and didn't look like a typical bluegill.
ShellCracker?? Good size mouth and very aggressive. Immediately after putting him in my tank he started fighting everyone and he is smaller than everything in there. My big green sunfish is the only one that didn't back down. I had to take him back to the private pond behind my neighbors house, He was just stressing my entire tank out.