
Hi John, WELCOME TO FISHLORE !
Popeye is nothing to wait on. Most meds are ok for fish that have scales. Tetras are the only fish I know of for sure that you have to be careful of, and with them they often tell you to use the med. 1/2 strength. I would suggest you quarantine your fish, and use Maracyn-two by Mardel. It is effective against pop-eye, and even if it is an injury it will help clear bacterial infections. Use as directed, and if you feel uneasy about the dosing, use 1/2 strength, but use for the entire time as directed.
Be sure to take any charcoal out of the filter before medicating, and use charcoal after full course of antibiotic to remove it from the water, then discard the charcoal after 24 hours.
Pop eye and many other infections can be caused by water conditions. What are your levels of ammonia, nitrite, and nitrate?
Water changes should be done to maintain a cycled tank at 5-10 ppm of nitrate. This requires at least 25-50% changes every week. Good luck and tell us how it goes.