Description

Nitrite is the intermediate nitrogen waste product in the biological filtration process. After fish release ammonia waste, bacteria convert it to nitrite which is still dangerous to the fish. In a healthy biological filter, bacteria convert the nitrite into nitrate which is relatively non-toxic to fish.
Nitrite poisoning follows closely on the heels of ammonia as a major killer in aquariums. Just when you think you are home free after losing half your fish to ammonia poisoning the nitrites rise and put your fish at risk again. Anytime ammonia levels are elevated, elevated nitrites will soon follow. To avoid nitrite poisoning, test when setting up a new tank, when adding new fish to established an tank, when the filter fails due to power or mechanical failure, and when medicating sick fish.