Not an expert, but I can tell you what I've heard/done. I know it's terrible waiting for a solution while your fish are sick. So, here's something to get you started.
The dosage for epsom salt is 1 tsp per gallon. Get some vases, or containers to tape onto the edges of your tank and put your girls in those for treatment. You'll want to change the water in the little containers every day so you can add new salt. It's much easier to treat in smaller containers and if your fish are having problems getting to the surface, it will be easier in a shallow container. Some people recommend cooked pea or daphnia for bloating, but I've heard just as many people say it's a bad idea, so I'm not sure if you want to give it a try or not. I've never tried the pea or daphnia, but I have had the epsom salts work for me. Make sure you fast them as well. I hope your fish all get better!