I would suggest that the initial cause for the chunk missing from the Flame Tetra was not the rummynose, nor likely any of the other tetra. One can expect fish to pick at such openings after the fact, but not cause them. Akasha, in your dad's situation, was that a rummy?
Since you mention knocking a fish on its head...that is actually the quickest and probably kindest method to euthanize a fish. I've been doing this for years, and in an article in PFK a year or so back it was mentioned as the best. Clove oil is not as quick, nor is freezing, but a sharp knock to the fish kills it instantly with no pain. I net out the fish, wrap it in a paper towel, and give it a good smack with my hand on a hard surface. The paper towel quiets the fish and contains it, you can imagine the alternative. But it is instant.
Quick comment on the eye issue...fish with both eyes have very close to 360 degree sight. Losing half of that will obviously have a serious implication for the fish. They can survive months sometimes if they somehow adjust and nothing else picks on them.
Byron.
Since you mention knocking a fish on its head...that is actually the quickest and probably kindest method to euthanize a fish. I've been doing this for years, and in an article in PFK a year or so back it was mentioned as the best. Clove oil is not as quick, nor is freezing, but a sharp knock to the fish kills it instantly with no pain. I net out the fish, wrap it in a paper towel, and give it a good smack with my hand on a hard surface. The paper towel quiets the fish and contains it, you can imagine the alternative. But it is instant.
Quick comment on the eye issue...fish with both eyes have very close to 360 degree sight. Losing half of that will obviously have a serious implication for the fish. They can survive months sometimes if they somehow adjust and nothing else picks on them.
Byron.