What else can I add?

I've kept and bred mollys in pure freshwater and never had an issue with them. I would add some salt but my angel and some of my catfish are sensitive to it.But always had good luck with mollys. Had a very nice sailfin male molly I bred, he was orange with black speckles all over him. All of his siblings were all silvers, expect him.
 
I also keep mine in fresh, but they live much longer and breed better in water with higher salt levels. It's just not practical for me to set up a brackish tank, and I've had mollies live for quite a while, and produce some nice babies. Sounds like your sail fin was a cremescicle dalmatian cross. They're gorgeous. I currently have only one fry of that mix, and she seems relatively healthy. Of course, I may have more in the breeding net, but I've had way too many babies to keep tabs on them right now. :p

Gk
 
Adding NaCl salt won't really make your water brackish.. Brackish is more a lower concentration of Marine salt in the water... there are other chemicals involved.
 
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