Discus and water changes

[Poustic]

I don't think I should have used the word hormones in my attempt to explain. I am not sure what the right word would be though :roll:

I had some random thoughts after posting so here they are ... maybe they make sense.. maybe not.. :?

Pretend that this has nothing to do with discus.  Every environment can support so many of X species.  If the number of X is greater than the environment can support, something changes (ie not enough food)  and some X die.   IMO the variable that changes could be the reason that any of our fish die.

Your tank and maintenance schedule have a capacity of how  many fish can be supported. If the capacity is exceeded then the fish get stressed witch leads to sickness, stunted or slowed growth and death

Sounds like a thought I had earlier... since your typical fish isn't really a math wiz and might not be able to calculate the "space available" for deciding by how much to grow, or how many offspring would fit in the tank, nature makes them emit this "B.O.", and slow down their expansion depending on the level of "stink", so to speak.  And frequent water changes would basically trick them into thinking their environment is bigger than it really is by "Febreezing" all that....  :roll:

Just want to say I am glad someone ask this because I've the exact same thought at the beginning when I start my planted discus tank. I read many articles and all of them suggest to do frequent water change for discus... but i though because they are not planted tank and so, water change is necessary for them. but now, i know there is actually other reason behind the frequent water change....

Are you doing less frequent water changes?  And are your discus growing normally, or no?

[Flawed_Artist]

I'm very sure I have literature at home about a growth inhibiting hormone that was a problem for blind cave barbs, due to their natural environment - very well-stocked, but relatively few run-offs from water sources. This, according to the text, slowed down their growth, and triggered research into the subject. This research indicated that nitrates and nitrogenous wastes were very low, but, still, so was growth. Further research led to the discovery of that hormone, but I'm not sure if it's only that species, or barbs or related fish, or all, or whatever.

Also, I can give, to anyone who would like, several reputable sites, and several reputable texts that would back up my belief that the majority of fish put out hormones and other things, which not only inhibit fish growth, but also inhibit beneficial bacterial growth, plant growth and weaken immune systems. This has to do, from what I've read, dissolved organic compounds. Quick research from any forum reader into "DOC's" will support me. Much of what we excrete, with a few differences - carbohydrates, fats, pheromones, enzymes, phenolic and amino acids, and other materials, build up. Some of these are broken down, or even taken away, but certain ones like phenolic acids, from what I have read and talked to experts about, cause the aforementioned problems. Also, surprisingly, this thread has only mentioned nitrogenous wastes building up over time. My understanding is that phosphorous, certain trace elements (including ash) in fish foods, and, most importantly, carbonate and general hardnesses build up if you don't water change enough, or if you just add water. From what I have read/heard, carbon isn't able to take out everything, either, as some people think - apparently, carbon has trouble with certain (if not most) larger organic compounds, which is why things like chelated iron from plant fertilizers don't require you to remove carbon.

The point is, I believe that there is something that inhibits growth other than nitrogen counts. I believe that it's a hormone, and I believe it's related to the DOC's in water (freshwater), even if it's not a hormone. Sorry if I've sounded confrontational, just throwing what I've heard in.

- The Flawed Artist.

[mseguin]

I don't disagree with you that something about clean water helps fish grow, my point is just that it seems more likely to be something that is affecting the fish physiologically (such as impurities affecting ion channels) rather than a hormone or signal that "tells" the fish not to grow.

[Julie]

Discus immune system is comprised when water conditions start to deteriorate.  Major cause is lack of water changes.  The plants will absorb the nitrate but as mentionned above there are other factors to be taken into consideration.
Nitrate seems to acidify the water, which is similar to discus natural habitat; I've observed that as nitrates increase, water acidifies and my discus tend to start cleaning sites and laying eggs; they also become more skiddish.
Once other pollutants (such as beefheart) foul the water, nitrate increases but what is contained in the final by product (feces) - bacteria..... and of course ammonia in urine.  The filter will absorb the ammonia, but what becomes of the bacteria etc.  It stays in the water, this is what I believe inhibits their growth and depresses their immune system.  I don't use any form of chemical filtration in my filters; I water change.  Just as the tributaries are constantly being flooded by fresh h20.
The minerals dissolving as c02 dissipates will increase kh, which would be another fluctuation in parameters not appreciated- osmotic pressure - hard for the fish to process.
Juvies have a weaker immune system than mature adults.
Keeping them healthy in the first place is the key.

Julie

[BigDaddy]

Nitrate seems to acidify the water, which is similar to discus natural habitat; I've observed that as nitrates increase, water acidifies and my discus tend to start cleaning sites and laying eggs; they also become more skiddish.

It's not the nitrate that acidifies the water per say... it is the nitrification process.

You can add pure nitrate to water and it won't change the pH.

The nitrification process, however, strips hydrogen from ammonia and ammonium (NH3 and NH4), which results in more free hydrogen ions... which in turn results in a lower pH.

The minerals dissolving as c02 dissipates will increase kh, which would be another fluctuation in parameters not appreciated- osmotic pressure - hard for the fish to process.

Can someone please measure their well water kH straight out of the tap (bypassing softeners of course) and then again after 24 hours when the CO2 is gone......  ?

[Julie]

Nitrate is the end of the cycle.

Julie

[Julie]

Motomans post on water parameters is an example of the kh increasing after degassing.
It's certainly not the ro water adding carbonates.

Julie

[pegasus]

Can someone please measure their well water kH straight out of the tap (bypassing softeners of course) and then again after 24 hours when the CO2 is gone...... ?

How could there be CO2 in our well water? What is breathing down there?

[Julie]

Gremlins.  :wink:
Check out these links:
www.solodvds.com/tropical-fish/fish_tank_water.htm
www.atlantech.ca/articles/Dissolved%20Gases%20in%20Aquaculture.PDF

[BigDaddy]

Motomans post on water parameters is an example of the kh increasing after degassing.
It's certainly not the ro water adding carbonates.

Julie

I think we can all agree that motoman's situation isn't a good case for an impericle test.  Testing in an aquarium, where other factors are at play, isn't going to provide accurate results.

Two clean glass vials.... one with new tap water and one with 24 hour "aged" water.

In a perfect world, there would also be a control vial with 1kH of carbonate hardness for reference purposes...

[BigDaddy]

Nitrate is the end of the cycle.

Julie

I am aware of the nitrogen cycle Julie   :lol:

You had said "nitrate seems to acidify the water".  I was simply pointing out that nitrate, as a compound, has no impact on pH.

If we were to look at the compound that "acidifies" the water (to follow you line of reasoning) then we would point at nitrite.... since it is the conversion of ammonia/ammonium to nitrite that frees the hydrogen ions, resulting in a more acidic solution.

[Julie]

I think we can all agree that motoman's situation isn't a good case for an impericle test.  Testing in an aquarium, where other factors are at play, isn't going to provide accurate results.

Two clean glass vials.... one with new tap water and one with 24 hour "aged" water.

In a perfect world, there would also be a control vial with 1kH of carbonate hardness for reference purposes...

Aged water would need aeration for an accurate result.
My discus tanks are bare bottom, there is nothing in them to alter the KH.

Julie

[mseguin]

I did a bit of reading, and found a study showing that stress from handling, etc, increases the levels of a protein that binds a growth horm,one. However, from the sounds of it, this wouldnt necessarily slow down growth, just de regulate it, so you could get defornmed fish, odd sexual maturity age, etc. Also, I dont know whether fish would emit this protein under regular aquarium stress.

[Julie]

I googled a good article on discus in planted tanks from Tropica. SimplyDiscus advocates bare bottom tanks so there isn't a whole lot of info there; though lots of nice pics.

http://www.tropica.dk/article.asp?type=aquaristic&id=453



Julie

[mseguin]

Alright well I emailed Prof Cristofre Martin, a professor of developmental biology at U of O (his research is with zebrafish, and apparently he gave a talk to OVAS a few years ago on the topic). He agrees with me that a hormone (or growth factor) is not likely to be the cause of decreased growth. He also thinks that it is more likely to be impurities in the water, such as nitrogenous wastes, that are inhibitng growth. My hypothesis would be that they somehow interefere with the normal functioning of the fish, perhaps through interfering with osmotic pressure or respiration, or ion channels. This could be similar to how carbon monoxide asphyxiates you by binding to hemoglobin, preventing oxygen from being transported.

[mseguin]

Here's a pasted copy of the email he sent me:

Nice to see you are part of the club.  I gave a seminar to the group a couple years ago on zebrafish.

I have also observed this phenomenon while raising zebrafish.  I don't know the answer but I would speculate that your second hypothesis is probably more correct for a couple reasons:

1)   In general, cells do not release factors that inhibit growth.  In fact, it is usually the opposite ... they release factors that stimulate growth.  This is very obvious in eukaryotic cell cultures (but these are not whole organisms).   There are examples, however, of bacteria and yeast releasing factors that inhibit cell division etc ... when nutrients become depleted or when there is crowding.

2)   But I observed this in our zebrafish systems to.   Because they are recirculating systems, if factors were being released into the water than they would still be there after the water flowed through the filters.  As far as I know biological filters do not remove things like steriods or hormones, growth factors etc. - but they do remove nitrogen wastes.

In my experience, larval fish are more sensitive to ammonia and nitrate, nitrites than adult fish ... so providing them with super clean water is a big benefit and they grow much more fast.

Just my two cents.

[Evan]

thanks Matt.  

I would think that swimming around  swallowing too much of your own waste would  lead to decreased growth or health in general.. :shock:

[discusFans]

Just want to say I am glad someone ask this because I've the exact same thought at the beginning when I start my planted discus tank. I read many articles and all of them suggest to do frequent water change for discus... but i though because they are not planted tank and so, water change is necessary for them. but now, i know there is actually other reason behind the frequent water change....

Are you doing less frequent water changes?  And are your discus growing normally, or no?[/quote]

i do a weekly WC of about 20-30%. they are growing pretty good so far... but i dont know the normal growth rate is, so i dont have anything to compare with.

[Julie]

Discusfans:pls post some pics of your discus and we'll have a look at them.

Another question:   Did you buy from the LFS?

Julie