if you have another tank that it can go in then yes remove it to give it good space and peace to recover, you'd need to set the filter for teh spare tank up with mature media from the main tank to cycle it instantly.
if not you can medicate the whole tank, you'll basically get a bottle and it'll say something like add 1ml for every 5 litres of aquarium water every other day for a week. So work out the quantities for your tank and just follow the instructions
make sure when you're treating that you keep water as clean as possible and provide the best nutrition that you can. just like with humans the better the conditions you are in the higher your chances of recovery
THanks for the explanation. I am assuming the bacteria meds won't harm the other fish?
Also, do you have a 2nd suggestion for what meds to get in case they don't have your 1st choice? I know that asking someone at the store isn't always the best thing to do.