A boy maintains anaquarium on a cold day he put a small heater inside the aquarium to make water in it slightly warm after a few hours he found all the fish dead what is reason behind it

A boy maintains anaquarium on a cold day he put a small heater inside

1.	A boy maintains anaquarium on a cold day he put a small heater inside the aquarium to make water in it slightly warm after a few hours he found all the fish dead what is reason behind it
Answer» H couldn't UNDERGO the sudden temperature CHANGE