On the subject of nitrite..

[enrgizerbunny]

I wanted to reply in a thread about this, but didn't want to derail the thread, so I made this one.

Where did the idea that nitrite is equally/more deadly than ammonia come from? I've seen it several times on this board and I must strongly disagree-except in very hard water, then it can be.

From the first moment I learned the nitrogen cycle, I understood that waste and uneaten food is broken down into less and less toxic chemicals. Ammonia, being the deadliest comes first, where low concentrations can cause serious damage or death. That is followed by nitrite, which is generally less deadly, but can be fatal in moderate concentrations. Nitrates are the least deadly, where high concentrations are required to kill fish.

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[Noviceafter2yea]

I wanted to reply in a thread about this, but didn't want to derail the thread, so I made this one.

Where did the idea that nitrite is equally/more deadly than ammonia come from? I've seen it several times on this board and I must strongly disagree-except in very hard water, then it can be.

From the first moment I learned the nitrogen cycle, I understood that waste and uneaten food is broken down into less and less toxic chemicals. Ammonia, being the deadliest comes first, where low concentrations can cause serious damage or death. That is followed by nitrite, which is generally less deadly, but can be fatal in moderate concentrations. Nitrates are the least deadly, where high concentrations are required to kill fish.

Sent from my SCH-I435 using Aquarium Advice mobile app

Any chance the thread was mine At a Loss, by Noviceafter2years?

 

[Mebbid]

Nitrite is in fact quite toxic to just about everything.

Excerpt from an article:

Nitrite can be toxic in a number of ways.21 Freshwater fish rapidly take up nitrite through their gills, leading to high levels in their bodies. In freshwater fish, nitrite taken up through the gills can compete with chloride for the same uptake proteins, so in some cases of elevated nitrite the fish can suffer from chloride depletion. It has been observed that some freshwater fish (e.g., bluegill; Centrarchidae: Lepomis macrochirus) do not take up chloride via their gills, and these species are notably resistant to nitrite toxicity.22

The internalized nitrite then causes a number of internal disturbances, including loss of potassium from certain tissues (such as skeletal muscle) and the oxidation of hemoglobin into methemoglobin, which reduces the blood's oxygen carrying capacity. This can cause reduced tissue oxygenation, hyperventilation and heart rate increases. Many other biochemical pathways become altered as well, including steroid synthesis, vasodilation (blood vessel enlargement) and changes in internal levels of ammonia and urea. Nitrite detoxification in freshwater fish is accomplished by direct nitrite excretion and by internal conversion of nitrite into nitrate.23


Nitrite and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

 

[Pandicorn]

I've lost a tank to what I think was nitrite poisoning... It's absolutely horrible, I lost all but 3 fish (who are alive and kicking atm [emoji3]) when they die, it seems like their veins turn brownish. They pretty much drown, not because they're not oxygen, just that they can't use it. At all. Many fall to the ground, unable to do much but gasp for air... Sorry to be so gruesome, just wanted to add my knowledge

 

[enrgizerbunny]

I never said that nitrite is NOT deadly. I said that it is LESS deadly than ammonia.

I mean, it is simple lethal concentrations. Ammonia is deadly in concentrations <10ppm easily. Nitrite gets leathal >10ppm.

 

[Pandicorn]

I never said that nitrite is NOT deadly. I said that it is LESS deadly than ammonia.

I mean, it is simple lethal concentrations. Ammonia is deadly in concentrations <10ppm easily. Nitrite gets leathal >10ppm.

What. Do you mean 1 ppm? 10 ppm nitrite = dead fish

 

[pip walters]

Different fish will have different tolerence. As the article says, nitrite can be excreted by fish. Tolerence will also be influenced by other factors and parameters.

I have posted before, I once measured nitrite at 8ppm in a system containing two week old carp fry. The fish ate and grew normally with no apparent effect on their health.

Imo, because nitrite increases gradually, tolerence is high in many fish. If you were to drop a fish from zero nitrite into water with very high cocentration, then you would have a different story

Certainly with carp, a recommended maximum is 3.33 ppm, but as I say,,.different species will have different tolerances.

 

[jetajockey]

I think because it's dependent on various factors. Most fish tend to be more nitrite tolerant than inverts like crayfish, but the amount that they can tolerate varies a lot. There is a lot of conjecture about both short and long term effects like weakened immune systems and stunted growth rates from low level nitrite exposure.

I agree that the relationship is not linear as is often mentioned but rather both are equivalent in that they are both issues that need to be dealt with immediately.

Page 4 of this document has a chart with toxicity results on crayfish.

http://www.onema.fr/BFPP/bfpp/Article/376_377/376p705.pdf