The same thing occurs to all fish and living things when they die, indifferent of the type of material that they are living inside of; they decay and turn into organic matter.
Dead !!
It dies
A few seconds as it dies in agony.
It dies.
It dies.
it dies
It dies
it dies
It starts to smell like a dead fish.
it dies
Put it in a bowl of water with a lid on it and place it in the freezer. The fish basically goes to sleep, and dies as the water freezes.
Smoke from the air can settle in a fish's bowl, so the fish can breathe in all the second hand smoke just like a person would.