I have both in my 240. I really like both fish, but in different ways. It is a hard decision but I would get the RCW. Mine has a great personality and is the king of the tank. The only thing is that they will stir up the substrate quite frequently, so a clean tank is a challenge. As far as adding to your bio load they are messy eaters, because they like to beat their food against rocks. And when they do pieces go flying every where, so the smaller fish in the tank like to follow it around during feeding time.