just added 2 black mollies to my tank, already have a speckled one, thing is the speckled one has started attacking the other 2, nothing to serious, just seems to be pestering the life out of them, anyone any ideas why??, also the speckled one looks quite a size, big belly on it, we had 2 mollies but one died last week, so we just replaced, could the spec be preggers so its in the defensive?, the 2 black mollies are slightly different in appearance one has a big tail (like a u shape on its side) the other has a smaller tail & fins, is this different sexes, its the new black one with the shorter tail that seems to be getting the most attention off the speckled, thanks for any advice in advance!! 
