I have finally found the fish that was being so mean to the other fish, maybe someone could tell me a little more about it.
Sunburst Wag Moon Platy
(Sorry couldn't get the pic to paste in here. )
This looks exactly like the fish that I had. From what I read it is suppose to be a peaceful fish. Anyone have any ideas about why is would let lose on two of the others? (which was the orange molly and my swordtail)
Also, I have decided that I am going to get another tank, for the betta. I would also like to include the fiddler crab in it. So from what I have read sand would be preferred for the crab. Can I put these two together? I'm pretty sure that I read about this combo somewhere. How big of a tank? 5 or 10 gallon's? Does the crab need to stay in heated water?