People need to put their big boy pants on and just end the critters suffering. Nothing does that quicker than a sharp blow to the noggin' or piercing the brain/severing the spinal column at the base of the brain.
I'd be lying if I said I didn't shed a tear when I had to do it to my marine betta, which I had for about 13 years. But it was quick and over, no mistaking whether he was suffering anymore or not.
I find having "drugs" on location to anesthetize the fish can be dangerous if you have pets or kids. But no more dangerous than a rock full of paly's sitting out for your dog to lick or kid to touch
