Sorry I do not mean to disrail post, but how quickly did your severum grow out. I currently have a 2" in a 150G, and I am hoping he will stay larger then anothers mouth lol.
In answer to your thread, it sounds like you might have your bio-load pretty well maxed out for the time being. Maybe trade some fish in at LFS? Cute fish? maybe a Blue Dempsey they can be quite impressive looking.