Hi Celeste. Ric here--I work side by side with Gina here as we're part of Just Answer's Fish Team.
I'd just like to reiterate the problems you mentioned so that we're all on the same wavelength: Goldfish with damaged fins, missing scales and one goldfish floating to the surface and not moving.
Gina covered some basic issues such as water quality which you mentioned was fine as this is always the first place to look.
The treatment plan suggested by Gina, Pimafix and Melafix, was proper procedure as these two medicines are generally good starter treatments as they will not damage water quality due to the fact that they are all natural.
Celeste you wrote that you do regular water changes and that is excellent husbandry on your part and should always be continued.
What we're dealing with here is a stronger than usual bacteria as seen by the fin and scale deterioration and Swim Bladder Disorder as seen by the fish floating to the top and maintaining a stationary position. Note that some Swim Bladder Disorders are also caused by bacteria and I believe the same bacteria is causing both problems.
In a case like this I would advise that a stronger medicine be used to combat the bacterial issue. Maracyn is an ideal medicine for this situation. Listed below is a link to a page that will show you the product. Just follow the directions on the packaging label for use.
On a final note I'd like to mention two other things. Keep in mind that Goldfish are not tropical fish and an ideal temperature range for them is between 62f-72f degrees and also as Gina had stated, keep an eye out for the fish fighting as a 10 gallon tank is considered a tight fit for two goldfish.
You're doing a great job with the fish Celeste but unfortunately diseases still manifest themselves despite all of our efforts. Try the Maracyn and I think everything will work out ok.