Read back through your thread- I covered increasing the salinity earlier. Honestly, if I were you, I would hit walmart/chain store and purchase a 20-30g plastic storage bin. They run for less than $10 and you can probably find a Christmas themed one right now for $5 or less on clearance. If your running two filters on the 30g, just move one to this. If you dont have two, then purchase a cheap filter & move some media from your 30g into it. Temperature match & properly condition the water and move your goldie to this bin. It will be easier to treat her and you will not have to worry about increasing the salinity. Or find a 30g on craigslist cheap/free and move her to this. Its going to be very difficult to treat her with all of these other fish in such a small tank and this will be the best thing for her in general. Her salinity then can be very gradually increased over 48hrs to .1% (3.8grams/gallon) as I suggested earlier and possibly further if necessary.