Zero Nitrates, Water Changes.......Why?

[Drstrangelove]

Yeah, no worries.

http://joe.endocrinology-journals.org/content/214/3/409.full
http://ehis.ebscohost.com/eds/detai...c2NvcGU9c2l0ZQ==#db=edswsc&AN=000309784400001 - sorry, not a full article, but its the best i could find right now

http://ehis.ebscohost.com/eds/detai...NvcGU9c2l0ZQ==#db=edselp&AN=S0016648012003747 - again, not a full article, but you get the idea
http://lifes.nchu.edu.tw/upload/publish/2011830235013\2011AJP_Review.pdf
http://www.panamjas.org/pdf_artigos/PANAMJAS_4(2)_158-178.pdf

Thanks for the links. I can't read much (from work), so this may be a faulty reply.

Getting back to your post, based upon a cursory review, none of these studies were designed to or concluded that hormones in the water affect fish growth rate. If you disagree, I'll have to reread them more thoroughly and correct my reply or try to make one that is more appropriate.

They do discuss hormones and fish, although many seem related to internal hormonal levels and not something discharged in the water. That last part is the critical link: is the hormone in the water and does it affect other fish. That's the part that is really exciting.

This is not something that I have found although the study would be painfully easy to do and should be welcomed.

One need only create a tank with crowded conditions, place some of that water in a tank with uncrowded conditions and watch the fish not grow, or better yet, run the water through something like a chromatograph or spectrophotmeter. (Not sure which, or that it may be something else.) Hormones in a water aren't undetectable since they are chemical compounds.

Despite this, I can't find any study on this although I have found many regarding the effects of improper feeding, random feeding, reduced feeding, various nitrate levels, deficient vitamins (various), and stress on fish growth. Barring that I am not a very good user of search engines or that for odd reasons nothing has been published, the science community either does not take his as a serious study or considers the answer obvious.

Since I am at work, I'm not able to read through the links to any extent, but I'll do so later and revise my point of view if I prove my first remarks inaccurate.

 

[tomomothy]

+1


We need a scientist,i think tomothy is one, maybe with rockets but hey hes still gotta be smart!


And what exactly are growth inhibiting hormones? A compound?element?

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Go S.Vettel #1 RB8 3X WDC!!!!!!!!!





http://www.monsterfishkeepers.com/forums/showthread.php?504763-Cheap-plants-less-nitrate!-POTHOS

Thanks for the tip of the hat but I'm a physicist by education. We need a biochemist here for some legit data analysis

 

[petspoiler]

......................, the science community either does not take his as a serious study or considers the answer obvious.

.......

I'm venturing a common sense guess, that it's this ^
Live fish produce hormones, and their bodily excretions are going in the closed water systems which we keep them in.
We already know the hormones have biological effects inside the fish. We also know that fish absorb elements from the water they are in.
You can do big experiments. Or, just think about how humans are prescribed hormones which are derived from the urine of pregnant horses. Hence, "The Pill", HRT, and even gender change procedures for men.
Fish soaking in a load of bodily excretions will absorb them.
You seem to be wrestling with the premise that fish's excretions contain elements which are inside them.
They don't have a special whole-body excretion filtering mechanism which prevents that.
?

Also, a hormone does not have to "be produced for the purpose OF (fill in blank)", in order for it to "have the effect OF (fill in another blank)", when absorbed in any manner.

 

[Drstrangelove]

I'm venturing a common sense guess, that it's this ^
Live fish produce hormones, and their bodily excretions are going in the closed water systems which we keep them in.
We already know the hormones have biological effects inside the fish. We also know that fish absorb elements from the water they are in.
You can do big experiments. Or, just think about how humans are prescribed hormones which are derived from the urine of pregnant horses. Hence, "The Pill", HRT, and even gender change procedures for men.
Fish soaking in a load of bodily excretions will absorb them.
You seem to be wrestling with the premise that fish's excretions contain elements which are inside them.
They don't have a special whole-body excretion filtering mechanism which prevents that.
?

Also, a hormone does not have to "be produced for the purpose OF (fill in blank)", in order for it to "have the effect OF (fill in another blank)", when absorbed in any manner.

Well, we can't know what they are thinking or what they consider obvious. I'm not concerned that it does or does not exist as much as that no one seems to have tested for it. I'll keep looking since it's what I do, lol, but you'd think that some enterprising student wanting an easy and relevant dissertation project would have hopped all over this.

 

[pk705]

I would just like to note that broad stances such as "fish absorb elements from the water they are in" are not concise and offer little argumentative support.

Fish absorbing "elements" is not as common sense as you might think. For absorption of large molecules there usually needs to be a transport system. Since freshwater fish don't "drink" water in appreciable quantities (as it would completely destroy their osmotic balance), the gastrointestinal route is most likely out. Since gills have a selective membrane system similar to lungs that only lets very small molecules pass, they are most likely out as well. Absorption through the skin would most likely not influence most species either. And that is before we consider the nature of hormones that might be used - protein hormones would not be able to be absorbed easily as they are simply too huge. Taking into account the amount of energy invested into them and the amount of energy that bacteria would gain from degrading them, they are even less likelier. So, you are left with steroid hormones. In humans, steroid hormones have one simple problem - their water solubility is minimal, hence they are carried by protein carriers. In water, this too would not work well. So than we come to the potential of small molecules such as NO and similar. These are usually burdened by small half lives. (note: I have left out prostaglandins and similar polyunsaturated fat derivatives as they are plagued by the same problem as all others - they are too big to diffuse through small celled barriers effectively.) As for other metabolites - ammonia diffuses across gills readily, if the ambient concentration is too high, it cannot diffuse out of the body and the fish dies (ammonia is toxic in humans as well, impaired metabolism causes nerve damage and a bunch of other stuff). Nitrite can pass through the gills and binds to haemoglobin, suffocating the fish. Nitrate is too big/charged to pass through the gills and is therefore relatively harmless. Usually hormones in waste are degraded to a point where they are no longer biologically active (gut bacteria, etc.).

If there are such substances that act as signals, I would very much be intrigued not only by their existence but method of action as well.

Since we're talking about "wrestling with premises" - you seem to be wrestling with the premise that fish, like humans or bacteria have a metabolism.

As for why the pill and similar examples are a false equivalence - those hormones have all been artificially synthesized and have a well documented way of absorption. You have failed to present a similar case for fish in any way. Fish do not soak in a load of bodily excretions. Fish swim in a highly diluted, highly metabolized environment with many different characteristics and organisms where logic would dictate that anything that can be digested by bacteria will eventually be digested by bacteria (as it always is). Human excretions contain minute amounts of elements which are inside them (mostly a) nitrogenous waste and b) indigestible food components).

I apologize if the above reply seems a bit harsh.

 

[cjack]

When I read the articles I noticed that the hormones were mostly internal as well. However, there has to be a way to remove these substances from their blood stream, which I assume is the liver. The liver then has to excrete these materials from the body, so while they might not be full fledged cortisol or other hormones, there has to be some material being excreted that could act in an inhibiting manner. I'm not really sure if that makes sense and/or if it is actually true.

pk705, while there are methods to decompose and break down most substances, the issue is the time required to. There was an article in Coral magazine a few months ago (I know its for saltwater, but hey, the assumption should stand) that discussed how sewage and waste water from Florida is partially to blame for the problems the Longspine Urchin are having with their reproduction. You did mention that birth control pills and other human intended hormones have been designed to be absorbed readily, but hormones that are inside the body are also fundamentally required to be soluble otherwise they wouldn't be effective. Sorry, I got a little off topic of time, but lets revisit. Being in the wild there is a constant supply of "fresh" water. But the problem is that when fish are kept in our tanks, everything that would be washed away by water from upstream, is still there all around the fish just building up.

 

[petspoiler]

I qualified my post with a gigantic claim of "common sense guess". my bad.
The question is, why are water changes needed for healthy fish when ammonia, nitrites & nitrates are all under control?
If you absolutely know what the reason is not, then you must have data on what the reasons are.
I assume that accurate research would reveal both aspects of the issue.

 

[dragonfish]

Have you talked to any of the people on aquaponic sites? Some of these guys may be able to give you more insight.

 

[Bderick67]

Have you talked to any of the people on aquaponic sites? Some of these guys may be able to give you more insight.

That's a good point, they raise a ton of fish in crowded conditions for human consumption. Will have to do more research on this end.

 

[David R]

Bumping this interesting discussion back up. How's that 700g pond going Brian?
Did you find out anything about aquaponics and their water changes?

Going back to my earlier post about trying to minimise the amount of water I need to change with my 2000L tank, so far the plan of light stock + pothos is working very well. In fact, I have barely been able to get a detectable nitrate reading (yes it is cycled, ammonia and nitrite at zero constantly), I've even been intentionally leaving the muck in the settling chamber of my sump and not cleaning out the foam in the filter to try provide more food for the pothos! Granted many of the fish still have a lot of growing to do (black aro, royal panaques, and L14 goldys are all less than half grown) and I do plan on adding a few more cichlids. I've been changing about 200L a week, mainly so I can do a siphon after feeding the plecs veges (massive amounts of crap produced overnight!). I'm tempted to skip a WC and keep an eye on the parameters just to see what happens.