As long as the corral is fake, leave it if you like it. And I may not like pink gravel but the next guy/gal might. It's to each his/her own. As for your fish, telecubby had the right idea in saying you need more hiding places. While you do have some nice larger pieces, thery offer little in the way of a refuge from agression. Clay pots are a cheap way of doing it, or if you have the cash, go for something a bit nicer. I personally would call your tank fine as it is, but if you want to do more go for it. I'd only go one, mabey 2 maro max(I am assuming with all malawis now you will only get more malawis). As your fish grow watch for increased sighns of aggression, or overcrowding. If it seems to be getting a bit cramped, sell/trade a few out or get another tank(I love new tanks). WHat kind of pleco do you have? If it's a common, that would be a concern. I'm sure you know about them being on this forum. Go get a smaller variety if that is the case, bristlenose, golden nuget, etc.