Question

What level of ammonia is toxic to fish?

Answer 1

Ammonia toxicity to fishes:

1. When ammonia concentration is higher than 0.01 ppm it is harmful to fish.
2. Any level greater than 1.0 ppm ammonia or nitrite can kill fish.
3. As the pH differs significantly from natural seawater, ammonium is toxic to marine fish.
4. Ammonia cause gill damage, internal organ damage, and skin damage and death.
5. The tolerance to ammonia may vary with individual species of fish. The young ones are more susceptible than the older ones.
6. Ammonia is a source of food for nitrifying bacteria. But it is harmful to fish.
7. The sources of ammonia are the excreta of fish. They excrete free ammonia from their gills and ammonium in urine.
8. Ammonia is produce from dead animals and uneaten food. As the material decomposes, nitrogen is released and converted to ammonia by bacteria.

Therefore ammonia is harmful to fish even low levels.