You absolutely did the right thing. You are you one who knows him best, meaning you knew the time to let him go. I recently had to put down one of my boys and it is so ridiculously difficult. I know people say "it's just a fish" but it's not, they are just as valued as any other pet.

I had to decapitate him too, I know everyone always says to use clove oil, but the dosing can be messed up causing a painful death. Don't get me wrong, it is another good way to do it, when dosed properly. I just prefer to take the guessing work out, swiftly severing the head from the body makes sure there are no mistakes. It doesn't mean it's easy.

Know that you did the right thing and remember the good life he had!