As to the use of a gun comment, I am not sure i could hit a fish, at least not any I own (maybe my bigger pleco, but definitely not a threadfin or khuli loach). And I am fairly decent with a gun. Besides digging the bullet out of wherever it winds up and explaining to the police why I fired a gun in my apartment are more than I'd want to go through for a fish. In the lab we overdosed them on MS222. It works good as long as you buffer the pH. Quick and painless (since it blocks neural conduction). Problems with home use: short storage life when mixed, and requires special disposal considerations.