Jpap, I found that set of links very interesting. They show quite a diversity of cichlics and the part about how a simple sandhead washing up across a sone bed can separate a group of one species for generations and cause them to no longer recognize each other as the same species years later if and when is washes away rejoining the area was mind boggling. I see now why being so "anal" about this setup can be something a person would want to do for good reason. 
