Originally Posted by ophiura
First, definitely be sure you have made an attempt to treat it.
Frankly, IMO the freezer is the best method for the fishkeeper, not necessarily for the fish.
In the absence of a fish anesthetic, which I would just slowly overdose, a fast, accurate, blow to the head is suitable, IMO. Don't do this unless you can really do it.
a blow to the head seems difficult if the fish is flopping around...in the case of my 1.5" clown there's no way i could smash its head without making it explode all over my kitchen.