This weekend I tried clove oil euthanasia, for the first time, on my yellow tang. First dose did put them to sleep, then second dose finished the job. The fish did not thrash about with the first or second dose, which made things a little easier.
The tang had gone blind early last summer. That was another first for me, a blind fish. Although it seemed to sense its surroundings quiet well, it could not pick food from the water column and would struggle to peck nori from a clip. For every 20 attempts at the nori, it may get 1 small bite. That average got worse as the months went on but I could not catch the fish. Finally it came out of its cave this weekend and was high up on the front glass panel. I had my fish net balancing on the tank ready for the last couple of months as well as clove oil on hand. Finally I caught it.
I had been offering nori at 3x my normal rate as well as weekly water changing at 3x the rate, in hopes the fish could find a way to power through and keep the extra food from fouling the water... The weight of the fish just kept declining.
Pic of anthias with YT hiding in its cave: