Nitrite more toxic than ammonia????

[ZoozFishMaster]

I was talking to one of the biology professors at my university and he tried to convince me that nitrite is more toxic to fish than ammonia. I have a hard time accepting this. Did anyone every hear this?

 

[steve-s]

Both properties lead to the fish eventually suffocating so I think the importance of which is more toxic is moot.

Ammonia can and will severely damage the gills (lamellae and primary filaments) refered to as gill hyperplasia preventing the fish from gaining O2 from the water and suffocating. The higher the level gets the less the fish will be able to excrete ammonia as waste. Nitrite oxidises hemoglobin into methemoglobin reducing the bloods ability to carry O2. Again resulting in the fish suffocating.

If fish are left in low amounts for long periods, either can cause severe bacterial problems.

In short, both should be equally concerning to hobbyest. Of the two though, ammonia is typically the faster killer. It really depends on if your comparing equal quanities of both...

Cheers
Steve

 

[malkore]

I would say ammonia is more toxic, only because the fish's gills never recover from the damage. Nitrite poisoning can be recovered from...but you could debate the stress induced by it takes months off the fish's life.