lost 1 of my sailfin mollies! 1 other sick ! need advice!

well guys the second spot grew bigger even w/ the chemicals and the salt. i lost my second female this morning and she was pregnant. I'm stopping the chemicals, doing a 50% water change and slowly going up to full salinity . i hope this all doesn't kill my 3 week old fry that are in there. they all look healthy. temps at 75f now. contacted the breeder and he told me the magic number is 82f for the treatments and salt to do their thing. i don't think any pathogen could jump to another fish w/ the meds. and salt that in there now could it? don't have a hydrometer yet but my hornwort is starting to die off so my salinity must be getting up there. i thought about netting her out but she was very pregnant so i was reluctant. hopefully the pathogen doesnt go to any of the other fish.

I really, strongly suggest that you use the salinity increasing time course published by another person who also published their mortality rate. And what species do you have? We should verify their salt tolerance before you try this.

As Mikez mentioned, water quality is important. With continuing deaths, it's time to test your ammonia and nitrate.

Buy:
hydrometer
ammonia test kit
nitrate test kit

and either tell us what species you have or e-mail the original seller and ask.

I would cull or quarantine infected fish right away. Considering you have an unknown pathogen, leaving them with other fish to possibly infect them, seems like a big enough risk to warrant quarantine or culling.

If the fish are typical pet store Sailfins they're most likely hybrids anyway. The two most common species of "Sailfins" are P. latipinna and P. velifera. Latipinna are often found in marine habitats, while velifera are an inland species. The easiest way to tell (assuming you're looking at a pure species) is how the dorsal fin attaches to the back. A latipinna has a long dorsal that is connected to the back almost its full length. A velifera has a small area of attachment about mid -back, and the fin flares up trails back, unconnected.

well I've done the water change and I'm going to do 10% water changes per week till' i get my salinity back down. no more spots noted on my remaining fish. i got 20 more fry so I'm not too worried about running out of fish. everyones seems real happy. once the fry get old enough to sex i might be interested in trading some of them for other wild livebearers.