# discus, waterchanges, and hormones



## lipadj46 (Apr 6, 2011)

The hormone thing is bunk, it was a misquote taken out of context by folks before the internet was widespread and is now more "LFS Lore" than anything. I don't know one serious discus person who believes it. It works more like this, the more food you feed the faster a fish will grow, the faster water quality will drop, the more water changes needed.


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## fplata (May 20, 2012)

Not so sure the hormone thing is a bunk, I am friends with a very reputable Discus breeder, who has a couple of books published on the topic of discus an he believes there is some truth to it, whether is a hormone or not we do not know, but the fact that the fish will not reach its maximum potential size in water that is not frequently changed is very true.


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## auban (Jun 23, 2012)

lipadj46 said:


> I don't know one serious discus person who believes it.


i know quite a few...


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## lipadj46 (Apr 6, 2011)

Go over and ask at simplydiscus and come back and report what they say. Again it is a myth that has been passed down the grapevine. If you you search over at simplydiscus you can find where the myth originated from

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## NWA-Planted (Aug 27, 2011)

The issue with hormones is not a myth and i will stand by that. There just has not been any big research done in the aquarium side to support or disprove the notion.

Do some googling there was a report on a river in the north where fish had steadily been decreasing in size. What they found was an overpopulation due to lack of predatory fish due to over fishing. Why is this important? When they examined the smaller than normal pan fish they found an over abundance of a certain growth hormone in their system which actually created an opposite effect in the fish stunting their growth. So why would this not apply in a fish tank which is a closed eco-system?

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## lipadj46 (Apr 6, 2011)

Saying stunting in an overpopulated system is due to GH hormones is cherry picking the research that is out there. Especially in an area where panfish and their predators are selected to be removed by fisherman due to size.

Also this is a bit off topic from the specific "discus anti growth hormone theory" where is goes something like this: Adult discus secrete an anti growth hormone that will cause stunting in other discus so they have less competition. This is the discus myth of lore that is written about in discus books. As far as discus stunting in a fish tank due to GH hormone in the water... Its a neat idea but to claim there is "proof" is silly.


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## NWA-Planted (Aug 27, 2011)

lipadj46 said:


> Saying stunting in an overpopulated system is due to GH hormones is cherry picking the research that is out there. Especially in an area where panfish and their predators are selected to be removed by fisherman due to size.
> 
> Also this is a bit off topic from the specific "discus anti growth hormone theory" where is goes something like this: Adult discus secrete an anti growth hormone that will cause stunting in other discus so they have less competition. This is the discus myth of lore that is written about in discus books. As far as discus stunting in a fish tank due to GH hormone in the water... Its a neat idea but to claim there is "proof" is silly.


I don't see how it's cherry picking, have you read the article it specifically talks about the growth hormone being something found in the pan fish. It's linking the fact that even in a river system once the population got to a certain the hormones became so concentrated that it is limiting the growth.

Please see link below
http://adventure.howstuffworks.com/...servation/fish-populations/fish-stunting1.htm

As to the proof with discus there is a two way street there. There is no definitive proof to confirm it and likewise there is no definitive proof to deny the claim.

What we do know about discus is that to grow them out you have to do large regular water changes. As to why,i have yet to see any definitive proof as to what the reason is, we must know it has to be done. Some say ammonia, nitrates, yada yada. The weird thing is there is no actual research to my knowledge that has been done on the subject. So until that happens i will stand by that growth hormones / hormones of sorts have effects on fish growth in aquariums not just discus.

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## lipadj46 (Apr 6, 2011)

Yes I've read that and its does not mention GH Hormone levels in the water stunting fish. It says external factors can impact hormone blood levels:

"Consequently, a shrunken diet stunts body development. A fish's growth is primary controlled by its GH hormone. The external environment can impact the concentration of GH in a fish's bloodstream, and, therefore, its growth rate. Ironically, stunted fish have more GH released in their bodies than regular fish. However, the stunting also makes them resistant to the hormone, thus limiting their growth [source: Evans]."


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## NWA-Planted (Aug 27, 2011)

lipadj46 said:


> Yes I've read that and its does not mention GH Hormone levels in the water stunting fish. It says external factors can impact hormone blood levels:
> 
> "Consequently, a shrunken diet stunts body development. A fish's growth is primary controlled by its GH hormone. The external environment can impact the concentration of GH in a fish's bloodstream, and, therefore, its growth rate. Ironically, stunted fish have more GH released in their bodies than regular fish. However, the stunting also makes them resistant to the hormone, thus limiting their growth [source: Evans]."


What the heck you mean it doesn't say that??? Did you read what you quoted right there it says stunted fish have more gh in their body!! The external factor is the fact there is an overpopulation therefore more of the hormone its right there in black and white

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## lipadj46 (Apr 6, 2011)

NWA-Planted said:


> What the heck you mean it doesn't say that??? Did you read what you quoted right there it says stunted fish have more gh in their body!! The external factor is the fact there is an overpopulation therefore more of the hormone its right there in black and white
> 
> Sent from my SCH-I535 using Tapatalk 2


Hormones are in their body, produced by their body, not absorbed from the water column.


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## NWA-Planted (Aug 27, 2011)

Ok i see what your getting at... Yes your right, but the stunted fish have a higher gh hormone concentration which is directly attributed to their stunted growth...

So what's encouraging the excessive release, external factors of overpopulation, and who is to say that there is not another hormone released into the water that triggers that? Fact of the matter is hormones can be absorbed and detected externally, thats why i firmly believe there is a limiting hormone that effects aquarium fish that does in fact build up in the water. Which is why water changes are important for growth, to remove those trigger hormones just as much as wastes

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## lipadj46 (Apr 6, 2011)

NWA-Planted said:


> Ok i see what your getting at... Yes your right, but the stunted fish have a higher gh hormone concentration which is directly attributed to their stunted growth...


Yes I agree, this is what the research says and is not a myth.



NWA-Planted said:


> So what's encouraging the excessive release, external factors of overpopulation, and who is to say that there is not another hormone released into the water that triggers that? Fact of the matter is hormones can be absorbed and detected externally, thats why i firmly believe there is a limiting hormone that effects aquarium fish that does in fact build up in the water.


This is the discus hormone myth/conjecture of discus lore. 



NWA-Planted said:


> Which is why water changes are important for growth, to remove those trigger hormones just as much as wastes


I do 100% changes a day on my discus growout tank.


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## NWA-Planted (Aug 27, 2011)

Would be nice to have a science group do an actual research on it and give us some solid answers!! 

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## dprais1 (Sep 12, 2012)

fplata said:


> Not so sure the hormone thing is a bunk, I am friends with a very reputable Discus breeder, who has a couple of books published on the topic of discus an he believes there is some truth to it, whether is a hormone or not we do not know, but the fact that the fish will not reach its maximum potential size in water that is not frequently changed is very true.
> 
> 
> Sent from my iPhone using Tapatalk


well, who?


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## lipadj46 (Apr 6, 2011)

NWA-Planted said:


> Would be nice to have a science group do an actual research on it and give us some solid answers!!
> 
> Sent from my SCH-I535 using Tapatalk 2


It would be yes. I believe it was Wattley that first came up with this theory and he was talking about a specific growth retardation substance secreted by the fish not really based on anything other than to try to explain why discus grow better in a tank with large water changes.


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## NWA-Planted (Aug 27, 2011)

I think i remember seeing that excerpt.

Hopefully we didn't derail this thread much.

Auban i hope you got some insight out of this!

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## dprais1 (Sep 12, 2012)

In response to original question....

UV is harmful to living organisms because of it's effect on DNA. 
Hormones are not alive and contain no DNA. 

Personally, I feel this whole thread contains an awful lot of drawing conclusions without justification.

My example would be diet soda

there is a link between diet soda consumption and obesity. Obese people consume more diet soda per person than non-obese people.

conclusion
1. diet soda makes people obese
2. obese people drink diet soda because they are obese
3. there are other variables at play that have not been explored

My point is simply that knowing two sets of figures does not mean you understand how they related.

As to the hormone question...

If I remember correctly, the stance of most on SD is that the hormone/stunted growth theory has never been proved---so it must be wrong.
But, I believe, it has never been disproved--- so it could well still be a valid theory.

Even the large WC theory has never been PROVED to my knowledge. It is just common knowledge. Of couse it was not that long ago that common knowledge also included the use of leeches to drain the body of 'bad blood.'

Lastly, simply discus is a great site, but it is also very 'cliquey' and those that don't adhere to the 50-100% WC everyday are generally mocked and laughed at and told they will fail. The posters on that site are hobbyists with different levels of education and knowledge and experiences. Most blindly repeat what others post. This does not make them experts.


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## auban (Jun 23, 2012)

UVC will destroy proteins, if not directly than indirectly as long as it produces something close to 254nm. 

ill set up a couple planted ten gallons and a couple groups of rainbows and see what happens. one with UV, one without. 

whether its proteins or what not, it will let me know if UV makes a difference.


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## dprais1 (Sep 12, 2012)

auban said:


> UVC will destroy proteins, if not directly than indirectly as long as it produces something close to 254nm.
> 
> ill set up a couple planted ten gallons and a couple groups of rainbows and see what happens. one with UV, one without.
> 
> whether its proteins or what not, it will let me know if UV makes a difference.



THAT is true!


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## NWA-Planted (Aug 27, 2011)

auban said:


> UVC will destroy proteins, if not directly than indirectly as long as it produces something close to 254nm.
> 
> ill set up a couple planted ten gallons and a couple groups of rainbows and see what happens. one with UV, one without.
> 
> whether its proteins or what not, it will let me know if UV makes a difference.


Definitely start a thread and let us know!

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## auban (Jun 23, 2012)

lipadj46 said:


> It would be yes. I believe it was Wattley that first came up with this theory and he was talking about a specific growth retardation substance secreted by the fish not really based on anything other than to try to explain why discus grow better in a tank with large water changes.


it was based on the observation that a larger fish placed with a smaller fish always inhibited the smaller fish, ie, even with plenty of food and clean water, the smaller fish never achieved the same size as the larger fish. fish that were raised together from the same age and size would eventually have one that would get larger and would achieve the full grown size, but none of the others would. if they were all separated into their own tanks, most of them would achieve larger sizes, especially if they had lots of water changes(makes sense).

if the largest fish was removed and put in a tank by itself, but kept on a central water system, they would grow the same as if the larger fish were still in the tank with them. something in the water it seems was the cause.

personally, i fully believe there is a factor that causes growth retardation. i dont really know what it is, but i do know that it has been shown and proven that fish and other predators produce a substance (scientific world calls them kairomones) that will have an affect on daphnia. in the presence of fish kairomones, daphnia will grow larger helmets and apical spines. i have even ran into problems with this in my elassoma gilbertis. i tried feeding the fry some daphnia ambigua, but they grew so fast that the smaller ones had time to grow longer apical spines. when the fry were large enough to eat them, they choked on the spines. i have noticed the same thing when i replenished daphnia cultures with tank water. if there were fish present that came from the same area that the daphnia were collected from(ie, the daphnia recognized the predators kairomones) they would respond with extended apical spines and increased production of males. a different kind of fish that the daphnia had never been exposed to would not elicit this response. its one of the reasons i keep labels on all my cultures now, about where they come from. 

the bottom line is, something affects growth and it is a known fact that fish influence the water in non-visible ways, beyond the simple water quality issues. nobody has ever been able to show what the "hormone" might be, but the same goes for the Kairomones that elicit response in daphnia. the latter is a scientifically documented phenomena while the former is an guess made by a whole lot of experience. personally, i dont think either one has less merit.


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## lipadj46 (Apr 6, 2011)

Have you grown out small discus with adults? I have and they are just as large as the adults. Again I have my own personal experience to back up my own observations. Try your hand at raising discus and then come back and let us know. This in no longer 1994, people have gotten better at keeping discus.


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