Just do lots of water changes and gravel cleans to remove any medication from the water. Clean the filter to remove any gunk in it. Wait a month and if the fish are ok for a month then look at getting more fish.
If you have a spare tank you could use it as a quarantine tank and put all new fish in it for a month to make sure they are free of diseases. Once the new fish have been quarantined and not shown any diseases for a month, then you put those fish into the main display tank.
If you don't have a spare tank you can use a 40+ litre plastic storage container as a quarantine tank.
If you have a spare tank you could use it as a quarantine tank and put all new fish in it for a month to make sure they are free of diseases. Once the new fish have been quarantined and not shown any diseases for a month, then you put those fish into the main display tank.
If you don't have a spare tank you can use a 40+ litre plastic storage container as a quarantine tank.
