# How much Nitrate can fish live with?



## YelowLab8706 (Jan 30, 2008)

Ok so I have been with my new 75g for about 4 weeks now(Already had 2 established canisters so beneficial bacteria is plentiful) and have been maintaining steady water changes and what not. But when I change my water the nitrates do not go down much. 
For instance, today I changed the water with it being at about 40 ppm... IS THIS TOO HIGH? But when I was done it only got to between 5 and 10 ppm. I was hoping for zero ppm, I took out about 50 gallons during this water change( about 67%) and it still didn't go down to zero. I know my tap has between 5 and 10 ppm but more close to 5ppm if anything. 
I just wanted to know if there was a cause for high nitrates after water changes was from my filters..... is this possible? And what could I do to reduce the nitrates chemically? Nitraban? Thats in a solution made by Tetra btw. Thanks for reading. Also, what is the safest highest point nitrates can get to in you tank before it becomes toxic for/effects the fish?


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## 2wheelsx2 (Dec 7, 2005)

I am not sure I understand you logic and what you're trying to achieve. You're trying to achieve 0 nitrate when your tap water has 10 ppm? Is your tank planted? What is going to consume the 10 ppm nitrate coming out of the tank to make it zero?

To do the math completely, you are change 67% of the tank's water at 40 ppm nitrate and adding back in 33% at 10 ppm, so the math is like this:

.67 * 40 + .33 * 10 = 30.1 ppm

Even if you changed 100 % of your water you would end up with 10 ppm since that's what is in your tap, so you've got me scratching my head on this one.


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## YelowLab8706 (Jan 30, 2008)

Lol ok. Well how can I reduce it? or is there no way to do so? Becaus eI'm not sure of exactly how much is ok.


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## Imaconvict (Feb 1, 2010)

Nitrates <50ppm is okay, if you have 10ppm Nitrate, congratulations good job.


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## YelowLab8706 (Jan 30, 2008)

awesome..... u solved all my problems guys. Thanks


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## Imaconvict (Feb 1, 2010)

You are certain we are talking Nitrates and not Nitrites, correct?


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## PfunMo (Jul 30, 2009)

I believe you will find nitrates slightly higher to give you more trouble with algea rather than from it bothering the fish directly. Algea consider it fertilizer. Mixed with too much light can give you too much algea.
I find looking for 0 nitrates to be like keeping a perfectly clean car. It might happen but not for long.


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## YelowLab8706 (Jan 30, 2008)

Yes i am certainly talking of nitrates not nitrites


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## Toby_H (Apr 15, 2005)

I commonly compare nitrates to cigarette smoke...

It would take an astronomical amount to cause "instant death" (probably several hundred ppm nitrate)... but any quantity can take it's toll over time...

Within the hobby 40ppm and under is a very common acceptable range...

Back in the olden days (the 80s) it wasn't uncommon for me to see nitrates as high as 100 ppm in my tanks... but my fish also only lived a few years... I lived, I learned, I do much much better now...


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## punman (Oct 24, 2003)

Is the question how much CAN they live with or how much SHOULD they live with?
I have tested people's tank water with Nitrates almost off the scale and no dead fish. Some fish can live with high numbers but that does not mean that they should. I do one-third tank changes every 10 days with moderately stocked tanks and the Nitrates are low (but not zero).


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## KaiserSousay (Nov 2, 2008)

*I find looking for 0 nitrates to be like keeping a perfectly clean car. It might happen but not for long*

*I commonly compare nitrates to cigarette smoke... *

More metaphors..
Please, keep them coming. 

Like diet soda, if you drink enough, you still get fat.


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## cjacob316 (Dec 4, 2008)

like alcohol, a little bit and you're fine, too much over time and it effects you long term, a night of binging, could equal death lol

having said that, having nitrates in the water sucks
say you have 20ppm in the tank, and you do a 50% water change, after wards, you still have 20ppm nitrates, so by the next wc you might have 30ppm, so you do another 50%, then you end p with 25ppm, your nitrates will continue to climb until you reach about 40ppm. at that point you remove 50% of the water or 20 ppm, you add back 10ppm so have 30ppm, then your nitrates climb to 40ppm and change water again

so it will take 40ppm before the water change, for water changes to not increase your nitrates, kinda sucks, but it could be worse

obviously if you increase the size of water changes then the "magic" number decreases

this is all assuming your nitrates increase by 10ppm between water changes, that rate also controls that number


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## Benaiah (Aug 18, 2009)

I think I read somewhere that excessive nitrates reduces fish growth. So my question: is that true?


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## oldcatfish (May 27, 2009)

I know that some of us have had this debate before, but high nitrates aren't necessarily harmful. I personally know of 2 very successful aquarists that rarely do any water changes (like once or twice a year) in their aquariums. Both have multiple tanks, grow incredibly large and healthy (and long-lived) fish.

Both aquarists also feed more, as well as stock their tanks more heavily than I do, plus they use less filtration. But what they do to keep their fish healthy----siphon the gravel very frequently to remove any excess food and/or waste.

Neither aquarists test their water so I can't say what their nitrate levels are...but they have to be very high. The results that they have achieved leads me to believe that something other than nitrates is involved with water quality/healthy fish.

**That being said....I go with the conventional approach. Lot's of water changes (I do at least 1/3 per week), and very careful feeding. To any non-experienced aquarist...I also recommend going with the conventional method....it's more reliable, and takes much less experience/skill.


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## PfunMo (Jul 30, 2009)

I think oldcat has hit it squarely on the head. Many can do many things outside the "rules". What it takes is the experience combined often with luck to be able to do it right. What works in a tank on the East coast may be a total bust somewhere else. Learning to recognize the difference is a big part of the game. Forums are a good place to take a small look at how others operate-- They may/may not be a good place to find the way for you to operate.


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## 2wheelsx2 (Dec 7, 2005)

cjacob316 said:


> having said that, having nitrates in the water sucks
> say you have 20ppm in the tank, and you do a 50% water change, after wards, you still have 20ppm nitrates,


I'm not certain if you are including other factors, but the math is total wrong here. If you change water with 0 nitrates from the tap, and your tank has 20ppm and you change 50%, you will have 10 ppm nitrates afterwards. 50% is the sweet spot, as you always reduce by half, so your nitrates will never climb by more than your weekly gain. So if you weekly gain in 20 ppm, the most you'll ever have is 40 ppm if you ever get there. If you change more than 50%, you will trend towards what's in your tap, whether you have 0 or 10 or 20 ppm, but you will never reach zero since you can never take out 100% of the water.


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## YelowLab8706 (Jan 30, 2008)

Lol well yea basically my question was what should they live with. I mean a person can live in a dumpster but that's not necessarily what people would prefer or be COMFORTABLE in. I want to be sure because my fish cannot really tell me how they feel in my tank. So I need someone to speak for em, and why not the fish gurus on cichlid-forum lol.


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## Toby_H (Apr 15, 2005)

I've check water parameters of well over a dozen local lakes, ponds, swamps, rivers, streams, creeks, etc... I've never once fodn any trace of ammonia, nitrite or nitrate in any of them...

So be it this was in North Carolina and Michigan, not South or Central America... but I'm quite convinced that in typical natural conditions, none ofthese pollutants exist...

Thus I am thoroughly convinced that zero is an ideal reading for them... so we should do our part to at least keep them quite low...

While the title of yoru thread does nto take "comfort" into consideration, every post you have made has made it clear proper fish keepign is your goal :thumb:


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## cjacob316 (Dec 4, 2008)

2wheelsx2 said:


> cjacob316 said:
> 
> 
> > having said that, having nitrates in the water sucks
> ...


I think you missed most of the post, did you read that he has nitrates in his tap water? so a 50% water change will not reduce his nitrates by half, because he's putting more nitrates back into the tank.


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## 2wheelsx2 (Dec 7, 2005)

cjacob316 said:


> I think you missed most of the post, did you read that he has nitrates in his tap water? so a 50% water change will not reduce his nitrates by half, because he's putting more nitrates back into the tank.


No I didn't. I wanted to keep the math simple, but I can do it with 10 ppm as well. It will never climb over what you have as the "base" nitrates plus the gain in the tank.

20ppm x .5 = 10 +10 = 20 in a 50 water change

If he gains 10 ppm a week, that's the same thing again the next week, and he still ends up with 20. That's what I meant by it never going up past 20.

If the gain is 20, it'll never go past 30, etc. Your math is only correct if he gain increase each week, or the nitrates in his tank increases. The gain is logarithmic, and asymptotic, not linear.


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## cjacob316 (Dec 4, 2008)

no see, you added the 10 in the tank, plus the 10 in the tap, but you neglect the nitrate increase between water changes if he gains another 10 during the week, he'll have 30ppm before the next water change, not still 20 ppm

20/2= 10+10(tap)= 20+10(weekly gain)=30/2=15+10(tap)=25+10(weekly gain)=35/2=17.5+10(tap)=27.5+10(weekly gain)=37.5/2=18.75+10(tap)=28.75+10(weekly gain)=38.75... until you reach 40/2=20+10(tap)=30+10(weekly gain)= 40

again this is based on a weekly 50% water change, your tap having 10ppm and your weekly increase in nitrate being 10 ppm


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## kingb4c0 (Apr 21, 2010)

If you wanna keep your nitrates low you can:
1. Keep your filters clean
2. Increase your W/C regimen (50%-75%) weekly
3. Use a prefilter like a filter sediment cartridge and carbon block
4. If you have a sump, add some plants (mangrove or moss) to your trickle
5. Vacuum your substrate frecuently.

0 ppm is almost impossible but under 40ppm is very possible. :thumb:


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## 2wheelsx2 (Dec 7, 2005)

Sorry cjacob316, you're right. It totally slipped my mind that I even though I calculated the 10 ppm in the beginning, I was forgetting to add it each incremental week. So yes, in a case where you have nitrates in the tap, the equation is no longer asymptotic, so the OP needs to change > 50% per week to keep the nitrates from steadily increasing, unless he uses something which absorbs nitrates (chemical or plants). Thanks for catching that.


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## Sir Tristen (Sep 16, 2009)

Actually, if you want to get really technical. Say he has 20 ppm nitrates and takes out half. The remaining half STILL has 20 ppm Nitrates, so he adds his other half at 10 ppm, and the mix becomes 15 ppm. If he gains 10 the next week, he will be at 25, and after the water change, 17.5 ppm and so on.

As far as the original question. I would also shoot for no more than 40 ppm


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## YelowLab8706 (Jan 30, 2008)

lol.... well i didn't mean to start up a math debate here but I got a lot of info that is helpful. Tank you very much guys.


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## Toby_H (Apr 15, 2005)

YelowLab8706 said:


> Tank you very much guys.


lol @ "tank you"... no pun intended!


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## LSBoost (Jan 21, 2010)

To reduce nitrate:
1. Large weekly (or more frequent) water changes. Vaccum everything when doing this.
2. Plants such as aquarium plants or terrestrial plants. Aquaponics
3. Algae scrubber
4. Coil Denitrator, anaerobic bacteria
5. Reduce feeding along with the above.


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## YelowLab8706 (Jan 30, 2008)

LMAO Toby caught it haha. That was a mistake at first bcuz i was typng so fast but it goes with the forum so I kept the "TANK you" like that lol.


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## simon.li (May 1, 2010)

maybe 60G?


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## kmuda (Nov 27, 2009)

Just add a couple of pennies here as I've had some heated debates on this in the past. I choose to research things from the science side.......

The problem with answering the question of nitrates is that very few studies are actually designed to determine the long term effects of nitrates on fish and none are designed to determine these impacts on "our fish". They are conducted by (or for) the commercial food fish industry to determine how high they can allow nitrates to get without impacting yield, which has little to do with long term exposure. However, I did find enough information to come to the conclusion that under 20ppm is where you need to be, with 40ppm being the top end.

Studies performed on Fathead Minnows (which, for some reason I don't know, appears to be the fish science uses to test this type of things) identified that the physiological effects of nitrates can be detected in the blood chemistry of fish in concentrations of 21ppm and these changes become "significant" above 40ppm.

Studies performed by NASA to determine how low nitrates would need to be maintained to support fish from "Egg to Egg" (as a renewable food source in space flight) was 25ppm.

Studies conducted on Gambusia in Florida Springs identified decreased fertility rates in nitrate concentrations as low as 1.5ppm.

Concentrations as low as 10ppm are known to adversely effect rainbow trout, chinook salmon, and cutthroat trout

Studies conducted on Stripped Bass, to identify the exact physiological impacts determined that excess nitrates:

1. Affects antibody production 
2. Increased number of immature red blood cells 
3. Lowered level of mature red blood cells (anemia) 
4. Higher count of monocyte (a specific white blood cell) 
5. Higher count of neutrophil (a specific white blood cell that is especially destructive to microorganisms) 
6. Higher count of TLC - Thrombocyte-like cell (a blood cell of nonmammalian vertebrates that promotes blood clotting) 
7. Higher levels of creatine (A nitrogenous organic acid found in muscle tissue that supplies energy for muscle contraction) 
8. Higher calcium values in the blood 
9. Lower Chloride values in the blood 
10. Autopsy revealed damage to the spleen, liver, and kidneys

Other conclusions reached:

1. Nitrate damages the gills and kidneys affecting osmoregulatory ability 
2. The observed changes are the result of a pathological response and not of a generalized stress response.

In a nutshell, all of the above means the fish are suffering from infection, severe physical stress, and tissue damage. Their blood is incapable of distributing sufficient oxygen, the immune system is in overdrive and has become deficient, and the kidneys are failing. Granted, this was at concentrations of 200ppm over three weeks, but you have to go back to information that suggests the relationship between time, nitrate concentrations, and impacts.... in that the same type of impacts can be expected at lower concentrations over a longer period of time. The smoking analogy is a good one, one I have used many times in the past.

As a result of the science, I work to keep nitrates well under 20ppm in all of my tanks.

On a side note, I keep South Amercians. The highest level of nitrates ever recorded in the Amazon River was in a nearly dried up section during drought, and that was 1.24ppm. In the Orinoco River (where a lot of South American fish come from, including Oscars) it was 80ppb (that's parts-per-billion.)


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## a7oneal (Dec 30, 2004)

kmuda said:


> Just add a couple of pennies here as I've had some heated debates on this in the past. I choose to research things from the science side.......
> 
> The problem with answering the question of nitrates is that very few studies are actually designed to determine the long term effects of nitrates on fish and none are designed to determine these impacts on "our fish". They are conducted by (or for) the commercial food fish industry to determine how high they can allow nitrates to get without impacting yield, which has little to do with long term exposure. However, I did find enough information to come to the conclusion that under 20ppm is where you need to be, with 40ppm being the top end.
> 
> ...


There is very good information here, IMO. I try to take things from a science POV, as well, and I haven't ever actually looked this up, so thanks for getting my butt in gear!

I, too, have tried to keep my nitrates to the figures you listed. I just tried to keep them down.

It's hard to compare our un-natural tanks to what is happening in Nature. There are so many factors that go into why readings are typically low (including that lakes and rivers are probably understocked in comparison, and get infusions of new water frequently), though there are times when measureable amounts are detected. I believe in cases of high runoff through fertilizer laden areas are one example. Feel free to correct me on that, I'm going off my memory.

One thing I did find, FWIW. . . the maximum allowable nitrate levels for drinking water, according to the EPA, is 45 ppm. That's near the maximum that was recommended in the article summations provided above.


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## kmuda (Nov 27, 2009)

Anyone who wants to read the scientific data, below is a list of some of the science reviewed articles I had found in the past (I was writing an article on the subject for another web site).

You can google them to see how many remain online...

References: 
Camargo, Julio A., 2004, Nitrate Toxicity to aquatic animals: a 
Review with new data for freshwater invertebrates, Chemosphere 
58 (2005) 1255-1267

Colt, J., Tchobanoglous, G., 1976. Evaluation of the short-term 
toxicity of nitrogenous compounds to channel catfish, 
Ictalurus punctatus. Aquaculture 8, 209ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å"221

Edwards. Thea M., 2006, Water Quality Influences Reproduction 
In Female Mosquitofish (Gambusia holbrookie) from Eight Florida 
Springs, Environment Health Perspectives, Vol 114, Supplement 1

Hrubec, Terry C., Nitrate Toxicity: A Problem of Recirculating System, 
Aquatic Medicine Laboratiry, Virginia-Maryland Regional College 
Of Veterinary Medicine.

Kincheloe, J.W., Wedemeyer, G.A., Koch, D.L., 1979. Toler- 
ance of developing salmonid eggs and fry to nitrate 
exposure. Bull. Environ. Contam. Toxicol. 23, 575ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å"578

Scott, G., Crunkilton, R.L., 2000. Acute and chronic toxicity of 
nitrate to fathead minnows (Pimephales promelas), Cerio- 
daphnia dubia and Daphnia magna. Environ. Toxicol. Chem. 
19, 2918ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å"2922

Shimura, Ryuji, 2004, Nitrate Toxicity on Visceral Organs of 
Medaka Fish, Oryzias latipes : Aiming to Raise Fish From Egg 
To Egg in Space, Biological Sciences in Space, Vol. 18 No1 
(2004):7-12

DELLAMANO-OLIVEIRA, Maria JosÃƒÆ'Ã‚Â©, SENNA, Pedro AmÃƒÆ'Ã‚Â©rico 
Cabral and TANIGUCHI, GlÃƒÆ'Ã‚Â³ria Massae. Limnological characteristics 
and seasonal changes in density and diversity of the phytoplanktonic 
community at the CaÃƒÆ'Ã‚Â§ÃƒÆ'Ã‚Â³ pond, MaranhÃƒÆ'Ã‚Â£o State, Brazil. Braz. arch. 
biol. technol. [online]. 2003, vol. 46, no. 4 [cited 2006-11-03], pp. 641-651.

Mayorga, Emilio, 2002, Processing of Bioactive Elements in 
the Amazon River System, The Ecohydrology of South American 
Rivers and Wetlands. IAHS Special Publication no. 6, 2002

Lewis, William M., 2006, Concentration and transport of dissolved 
and suspended substances in the Orinoco River, Biodegradation Volume 
7, Number 3 / May, 1989, 0923-9820 (Print) 1572-9729 (Online)


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## prov356 (Sep 20, 2006)

Thanks for all of that info *kmuda*. I knew there were studies out there. I'm going to have to save the link to tis thread for the next couple of dozen times this question comes up.


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## kmuda (Nov 27, 2009)

And a dozen times after that. It's why I initially performed the research, to have something more than "My dad never changed water and his fish did fine" as the bases for recommendations.


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## a7oneal (Dec 30, 2004)

I appreciate the sources, as well. Thanks a bunch!


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## PortiaD (Mar 7, 2011)

oldcatfish said:


> I personally know of 2 very successful aquarists that rarely do any water changes (like once or twice a year) in their aquariums. Both have multiple tanks, grow incredibly large and healthy (and long-lived) fish.
> 
> Both aquarists also feed more, as well as stock their tanks more heavily than I do, plus they use less filtration. But what they do to keep their fish healthy----siphon the gravel very frequently to remove any excess food and/or waste.


Perhaps I'm missing something, but how do they siphon the gravel without changing the water?


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## John27 (Jun 6, 2010)

Benaiah said:


> I think I read somewhere that excessive nitrates reduces fish growth. So my question: is that true?


I believe that. I have 15-20ppm nitrate out of the tap, so I do frequent, large water changes at keep all my tanks around 20-30ppm. My fry tank, however, gets DAILY 90% water changes and is kept around 15-20ppm like the tap, and my fry grow, I would estimate 30% or worse, slower than typical fry. They are healthy, but they definitely grow slower than what I see with other folks.


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## Marcel G (May 3, 2013)

I just want to point out, that in your original article on OscarFish.com (http://www.oscarfish.com/article-home/w ... icity.html) you make one BIG mistake: you confuse mg/L NO3-N with mg/L NO3 !!! 1 mg/L NO3-N = 4.43 mg/L NO3 !!! So if someone states that some fish can survive 100 mg/L NO3-N, that means that it can survive 443 mg/L NO3. So if the scientists recommend to keep NO3-N levels under 25 mg/L, it means that they recommend to keep it under 110 mg/L NO3 !


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