That dempsey is getting big, has he started digging yet?
They can be bad for that once they start to mature. Of course, that is more of a breeding behavior and sense he doesn't have any potential mates in there it might not be a problem for some time now.
Not yet, but I'm waiting for that to happen. He's very calm and peaceful, unlike any cichlid I've ever had. It's probably because he's still a juvenile.