You can use just about any molly. I have a good mix of saltwater mollies right now; orange, white sailfin, couple dominoes, and some freaky goldish/transparent one. I have lost two but they were beat up by the 2 big males, not from acclimation. experiences seem to be that the breeds with big dorsal fins (sailfin) tend to do better in full strength seawater, but my experience is that just about any will do fine if acclimated properly. Just about every mollie available now is a hybrid anyways, and from what i read they are all one spieces, just different breeds (like dogs) so it shouldnt matter. Just be carefull, once they start breeding you're gonna have a whole lot of babies within a very short time. good luck