P. latipinna can be kept in SW, fishbase discribes them as being abundant in tidal ditches and brackish canals and i have heard several florida residents say that they have found sailfins in full SW. i myself have a 2 1/2" white sailfin molly in my 29g reef and have an online friend who had a breeding group in his SW tank as well. i do agree though that the P. sphenops molly is a primarily FW fish and won't do well in a SW tank. the problem is that the aquarium mollies are almost always hybrids of the two, and more, species of mollies so you can't just put any molly into a SW tank, try to find those with obvious sailfin lineage in them, i had two mollies that i acclimated into the tank, one was the white sailfin and the other was a beautiful orange cremesicle sailfin. i acclimated them over the course of about an hour by adding a little bit of water from the tank into the bag every 5min or so until the salinity matched, the white sailfin has been doing great for the last 6mo(dispite getting his sailfin shredded by my damsel, although it grew back within a day and a half) but the orange molly died after about a month, i believe because he was much more of a hybrid and it probably wasn't the best idea to put him in the first place but i didn't see any signs of stress while acclimating or for the first couple days and by the time he did it was too late to take him and i waited too long to get him into a FW tank.
