Is there a way to grow a fish to its max potential size in home aquariums?

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Interesting. I am not dismissing the notion that Nitrate is something like a canary in the coalmine; the main observable, quantifiable pollutant in aquaria that indicates a buildup of waste that would otherwise cause most of the health issues encountered by fish in improperly maintained systems


It can serve that purpose but a calendar can also tell you when to change water.

Of course, a lot of people still think nitrate itself is fairly toxic.
 
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I consider nitrate chronically toxic, and a growth inhibitor whether others "believe" it or not.
We only to need to look at the HLLE and other diseases that occur in older oscars and other adult cichlids to see the obvious long term damage these excess nutrients have done in many aquariums. When I test water in nature, nitrates are usually undetectable, so to assume a jump to 20 or more in aquaria would not have negligible effects is a bit of a stretch.
And when these disease posts come up, if I question water parameters , nearly every one answers with an average nitrate in the 20ppm or above, with a paultry water change schedule to match, and fish in too small tanks.

I do concede if aquarists chose fish evolved to match their tap water parameters, instead of "I want it, so I'm gonna get it", there'd be a few less posts in the disease section. Its usually a combination or stress related issues that bring it to a disease point, but eliminating even a few important ones can go a long way.
And nitrate is one of the easiest to remove, by just doing enough water changes.
 
I consider nitrate chronically toxic, and a growth inhibitor whether others "believe" it or not.

Opinion.

We only to need to look at the HLLE and other diseases that occur in older oscars and other adult cichlids to see the obvious long term damage these excess nutrients have done in many aquariums. When I test water in nature, nitrates are usually undetectable, so to assume a jump to 20 or more in aquaria would not have negligible effects is a bit of a stretch.

Citation required. Conflates nitrates with all nutrients (citation still lacking though).

I do concede if aquarists chose fish evolved to match their tap water parameters, instead of "I want it, so I'm gonna get it", there'd be a few less posts in the disease section. Its usually a combination or stress related issues that bring it to a disease point, but eliminating even a few important ones can go a long way.
And nitrate is one of the easiest to remove, by just doing enough water changes.

Well, we know nitrates are not one of the nutrients that contributes to disease. Maybe it's high DOC or low dissolved oxygen?

Has there been definitive scientific evidence of the cause of HLLE in cichlids? For certain captive marine fish it's activated carbon.


The naturalistic argument is weak. Just because nitrate is higher in captivity doesn't necessarily mean it's toxic. The scientific consensus is that it's not.

Now, why don't we apply the same argument to stocking density? Lighting? Ammonia? Nitrite?

The levels of ammonia and nitrite in natural waters is too low to be detected by colorimetric methods and certainly not by API kits.

So why aren't we demanding hobbyists take their water to laboratories for ion chromatography testing?
 
There is increasing evidence that accumulating water quality concentrations within low exchange WRAS can negatively impact cultured species (Deviller et al., 2005, Davidson et al., 2009, Davidson et al., 2011a, Martins et al., 2009a, Martins et al., 2009b). In particular, mounting evidence suggests that relatively low NO3-N concentrations, once considered to be harmless (Russo, 1985, Wedemeyer, 1996, Colt and Tomasso, 2001, Timmons et al., 2001, Colt, 2006), could cause chronic toxicity to various species cultured in WRAS that are operated with minimal water exchange. For example, Hamlin (2005) concluded that NO3-N concentrations accumulating within WRAS could be of concern for Siberian sturgeon Acipenser baeri. Hamlin (2005) determined that the 96-h LC50 for Siberian sturgeon (7–700 g) ranged from 397 to 1098 mg/L NO3-N and cited anecdotal evidence that concentrations as low as 90 mg/L NO3-N resulted in increased mortality.
The entire study is here
Comparing the effects of high vs. low nitrate on the health ...www.sciencedirect.com › science › article › pii
 
Here's a great example of what happens when you're irrationally fixated on something:


duanes blames nitrate levels of >20, I say it's anything but that.

OP lowers nitrate levels and doesn't investigate any other possibilities.

Fish die anyway.

Guess it wasn't nitrate!

Good job, duanes.
 
The maximum potential size is a freak of nature as far as I understand. Take a look at Robert Wadlow, world's tallest documented person to live.


8'11" and still growing when he died, one could say that is the maximum height for humans, will any of us reach it? No. I would say in my personal opinion that you should take those "max sizes" and accept that not every fish is going to hit that in some species. However my opinion is just that, an opinion.

Major diff is that he grew like that from a genetic disorder (acromegaly aka gigantism)...that isn't a normal max size say under ideal conditions. Andre the Giant also had this disease and died at around 48 (max life expectancy with this disease is 50).
 
I consider nitrate an indicator of problems in the acute sense, and only one part of the many problems in aquariums,
but ......it is the easiest testable indicator we have available, and one of the easiest problems to remedy just by doing a few extra water changes.
Of course water changes are not a panacea, but are often the best thing to do do in straightening out a bad situation.
When something goes awry in my tanks I try to investigate every possibility
(PDF) Nitrate Toxicity: A Potential Problem of Recirculating ...www.researchgate.net › publication › 267377185_Nitra...
 
There is increasing evidence that accumulating water quality concentrations within low exchange WRAS can negatively impact cultured species (Deviller et al., 2005, Davidson et al., 2009, Davidson et al., 2011a, Martins et al., 2009a, Martins et al., 2009b). In particular, mounting evidence suggests that relatively low NO3-N concentrations, once considered to be harmless (Russo, 1985, Wedemeyer, 1996, Colt and Tomasso, 2001, Timmons et al., 2001, Colt, 2006), could cause chronic toxicity to various species cultured in WRAS that are operated with minimal water exchange. For example, Hamlin (2005) concluded that NO3-N concentrations accumulating within WRAS could be of concern for Siberian sturgeon Acipenser baeri. Hamlin (2005) determined that the 96-h LC50 for Siberian sturgeon (7–700 g) ranged from 397 to 1098 mg/L NO3-N and cited anecdotal evidence that concentrations as low as 90 mg/L NO3-N resulted in increased mortality.
The entire study is here
Comparing the effects of high vs. low nitrate on the health ...www.sciencedirect.com › science › article › pii


This is the 2014 paper by Davidson who has refined his experiments over the years up until the 8-month Atlantic salmon study where the graph I posted earlier originates. In the 2014 paper, he states that many parameters weren't controlled between the two groups and that the difference in potassium could have explained the results.

In the 2017 paper, the experiment does a better job controlling variables and is of longer duration. Davidson notes that the abnormal swimming behavior from the 2014 study did not occur.

You do realize these are nitrate-nitrogen value, right? Well, maybe not since I remember you once said the regulatory limit for nitrate was 10 mg/L nitrate...

That means 397 mg/L NO3-N is 1,757 mg/L nitrate and 1,098 mg/L NO3-N is 4,860 mg/L nitrate. While these values are quite a bit lower than for most species, they aren't exactly great evidence that low levels of nitrates are toxic...

And this is what you see if you actually bothered to spend some time reading the papers on nitrate toxicity...LC50s in the 4,000-8,000 range.
 
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