Old fashioned fool here but I have no medications or any kind....I use Mother nature's best medicine...fresh, clean water with zero additives.
Fish with injuries or signs of a potential health issue, I reach for my water change gear and I water change every day until the issue has cleared up
My dad taught me decades ago that despite the fancy adverts and shelves full of medications etc, the best way to treat fish injuries like torn/bitten fins, scrapes etc is a 75% or more dose of clean fresh water every single day....and that method has not let me down.
I'm afraid that it is a pet hate of mine the way some people dive straight for the chemicals and bypass the water. And anything with "fix" in the name is an absolute nightmare. The times I have come across people with labrynth fish who have used "fix" medications/tonics and lost their fish as a result.
I will never ever understand how a shop employee with zero vet training can diagnose a fish issue, without seeing the fish, and effectively prescribe/recommend harmful chemical treatments.
Sorry but this is something I am passionately against, the use of medications when no confirmed diagnoses or illness or disease is present. Fresh clean water every day is 100% natural and clean water can heal alot of things and should always be the first port of call, only go for the medications/tonics on a vet's advice or as a last resort.