That medication is probably acriflavine which will then water green. Malachite green will turn it blue.
At this point, regardless of what type of aro you got, it’s a nice pet your friend gave you.
Just do a bunch of water changes, fill the tank to the top, and keep the water very clean. Add some salt and feed the fish good food and it should recover on its own.
If you read not to feed your fish during treatment, that’s likely to keep water quality up and ammonia down. Just do lots of water changes to negate that.
If you’re not seeing improvements a week from now, then you can think about meds again. Perhaps an antibiotic.