How bad really are nitrite levels...

[MattP725]

Well last night I moved my fish back from my little 20 g QT tank to my 55 g. The am levels were safe as well as everything else. Today however the am. spiked a tad but still not in a dangerous level but the nitrite (or nitrate whichever am turns into) is between 1.0-2.0. Is this a toxic amount? The QT tank is also in the beginning of a cycle so it has too high an am level at the moment although I could do a massive water change if needed. Should I be concerned? I am pretty sure that they will live it out because the all appear in good health and they made it through a bad ammonia spike before. What does everyone think?

 

[phases99]

Nitrite is highly toxic even in low amounts. You need to start doing water changes and get it down to 0 if possible. Fish do not get used to bad water conditions, eventually they will succumb to disease and die.

 

[Atari]

The analogy I always use is carbon monoxide and people. It binds with haemoglobin and as a result drastically reduces the oxygen carrying capacity of blood.

This is what nitrites do to fish in the aquarium, so any detectable amount should be cause for concern. Even if the levels aren't high enough to be fatal they will most likely have long term effects on the health of the fish.

Water changes are paramount.

 

[malkore]

Ammonia is converted to NitrIte. NitrIte at 2ppm is toxic, and like Atari says, it basically starts blocking the fishes ability to absorb oxygen into the bloodstream, thus suffocating it.

Some fish tolerate nitrites better than others, which can die when nitrites get above 0.00ppm.

Water changes are needed, possibly every day, until nitrites are back in check.

 

[yellow]

Sorry to revive a super old thread, but just in case someone googles this question and finds this thread, here's some important information:

Nitrite is toxic to most freshwater fish, but is harmless to marine fish. The chlorine in the salt water protects against nitrite toxicity. People have tested this. What would be ridiculously high nitrite levels to freshwater fish have no impact on marine fish. (But if you have detectable nitrite, be aware something fishy is going on with your bacteria. Your fish may have just lived through an ammonia spike, which is terrible for fresh and marine, so will need careful monitoring)

Incidentally, nitrAte levels don't appear to harm fish. Again people have tested this with insane high levels of nitrAte and there's no effect on the fish. That being said, many people sensibly use nitrate levels as an indicator of possible build up of other crud in the water, and use it as an indication of when to do a water change, and that's fine. But nitrate itself isn't harmful. Some people tell beginners that nitrate is toxic, to scare them into doing water changes, which is an effective tactic, but not *technically* true.

Well, okay, EVERYTHING is toxic in high enough quantities (if you drink too much water you'll die! Only takes about six litres in a few hours.) but the level of nitrate you'd need to kill half your fish is well over a THOUSAND parts per million. So don't worry about twenty. Just as you wouldn't worry about someone having a glass of water. So, if your fish are dying, don't blame the nitrate. Don't stop looking for the real reason; something else is going on.

 

[Caliban07]

Sorry to revive a super old thread, but just in case someone googles this question and finds this thread, here's some important information:



Nitrite is toxic to most freshwater fish, but is harmless to marine fish. The chlorine in the salt water protects against nitrite toxicity. People have tested this. What would be ridiculously high nitrite levels to freshwater fish have no impact on marine fish. (But if you have detectable nitrite, be aware something fishy is going on with your bacteria. Your fish may have just lived through an ammonia spike, which is terrible for fresh and marine, so will need careful monitoring)



Incidentally, nitrAte levels don't appear to harm fish. Again people have tested this with insane high levels of nitrAte and there's no effect on the fish. That being said, many people sensibly use nitrate levels as an indicator of possible build up of other crud in the water, and use it as an indication of when to do a water change, and that's fine. But nitrate itself isn't harmful. Some people tell beginners that nitrate is toxic, to scare them into doing water changes, which is an effective tactic, but not *technically* true.



Well, okay, EVERYTHING is toxic in high enough quantities (if you drink too much water you'll die! Only takes about six litres in a few hours.) but the level of nitrate you'd need to kill half your fish is well over a THOUSAND parts per million. So don't worry about twenty. Just as you wouldn't worry about someone having a glass of water. So, if your fish are dying, don't blame the nitrate. Don't stop looking for the real reason; something else is going on.

Nitrate toxicity as well as nitrite toxicity is an function of time, quantity, species, temperature, water chemistry etc etc. Lots of variables. I suspect most people have enough chloride in tap water to offset the effects of nitrite levels without even realising. Fish size and species play huge roles too. If exposed long enough methemoglobin accumulates in the fishes cells and 'suffocates' them but fish have the ability to counteract this phenomenon using reversal techniques but each fish is different and the rate at which they can do this will vary. Having said that, you'll be hard pressed to find any nitrite or nitrate toxicity supporting data for the types of fish we keep. Almost all studies are for cold water fish. The one study that I can recollect is one on guppy fry and the ppm required to kill half of the fry over 96 hour period was about 800ppm.

I'm not going to fret over 40ppm nitrate. I dose close to that every week.

What is more important as you quite rightly point out is what high nitrate levels represent. High BOD, reduced oxygen, water pollution etc. The water needs to be clear and free of organic pollution to keep oxygen levels high. Oxygen supports bacterial growth which keep your fish safe.

Did a bit of research here some time ago.

http://www.aquariumadvice.com/forums/f23/nitrite-toxicity-discussion-301444.html

Can't remember what the conclusions were other than that I don't really worry too much about either.

 

[SJJensen]

Brand new 20-gal tank, no fish, no plants, high nitrite level

We had the tap water in for about a week, no plants of any kind, then had the water tested. High nitrite levels. [Or nitrate? My husband can't remember what he was told, and we know nothing about it.]

Everything I Google says it's from waste, either from fish poop or plant debris. Since we've had neither, what else is it? The tap water itself? Honestly, this is the best tap water of anywhere we've ever lived, so it's weird that this is happening. Side note, we live on the Iron Range in MN and do not have a water softener, so our water is hard.

Any ideas? Tips?

I just joined today and this is my first post, so please excuse my ignorance!

Thank you!

 

[Caliban07]

We had the tap water in for about a week, no plants of any kind, then had the water tested. High nitrite levels. [Or nitrate? My husband can't remember what he was told, and we know nothing about it.]



Everything I Google says it's from waste, either from fish poop or plant debris. Since we've had neither, what else is it? The tap water itself? Honestly, this is the best tap water of anywhere we've ever lived, so it's weird that this is happening. Side note, we live on the Iron Range in MN and do not have a water softener, so our water is hard.



Any ideas? Tips?



I just joined today and this is my first post, so please excuse my ignorance!



Thank you!

Probably nitrate that was ‘high’ particularly if you have hard tap water. What exactly are you looking for tip wise?