This atmospheric nitrogen can lethal to fish when the water is over-saturated (over 100 per cent) saturation with this gas. Research has shown that nitrogen embolism otherwise known as NITROGEN GAS BUBBLE DISEASE can occur with 103-118 per cent nitrogen saturation and cause a lot of fish casualties. Even the beginner will get to learn more about aquarium after reading this article. It is written in easy language so that everyone will be able to understand it. This condition can affect an aquarium fish when one is replacing the old aquarium water with slightly warm fresh water.