Try Angel Plus for fish medications.
https://angelsplus.com/collections/fish-medications
Or
Jehmco
https://www.jehmco.com/html/medications.html
Potassium permanganate on Ebay.com
https://www.ebay.com/itm/39142858703...QAAOSw2Fdei9y-
Everything Aquatics new website under construction....they sell fish meds too.
http://store.everythingaquatic.net/