WC, WC and more water changes!

[MarkGSmith]

I was just chatting with a breeder who has enlightened me as to why I change so much water. The theory is that juvenile Discus constantly secrete a growth inhibiting hormone. This is an evolutionary survival trick. If a group are trapped in a small body of water after the wet season then the hormone builds up and they do not outgrow the limited space/food supply. If they are in strong flow the hormone is washed away and they are free to grow to their full potential.
This is why we are changing water even though the fresh water tests exactly the same as the tank water! We can't test for hormones...I can't anyways.
Seems to make sense to me, what do you think?

[Kyla]

I have heard this theory, but I dont believe it has been proven true. Currently I consider it a myth. Would love to see scientific evidence or articles, if anyone has links etc

Search this forum about the topic of water changes and u will come across some interesting posts which explain that the water these fish come from has very low ph which inhibits bacterial growth and there is so MUCH of it flowing constantly... we can't duplicate this in our tanks, so huge regular water changes are the best way to reduce the build up of organic matter and waste and bacteria etc.

[MarkGSmith]

Yeah, all I know for fact is that they need lots of water changes. The experiments that I have read about point to more than just waste/organic matter build up but nothing is conclusive. I'd have a little wager that it is a combination of many factors including water quality/hormones/etc. (Then again I've always been a bit reckless!)

[Paul Sabucchi]

As a newcomer to discus I think the main thing is that changing a lot of water and often has proven to work while other alternatives seem to fail in providing the same results. Knowing why would be interesting but probably of scarce practical use as chances are that changing water is always going to be easier/cheaper than intervening on the actual cause whatever it/they may be. Regarding the bacteria in the Amazon basin I had a look at some research papers and bacterial counts in the water are just moderately lower than in other relatively unpolluted waterways elsewhere. It would be surprising if the waters were practically sterile, devoid of bacteria (and the viruses that go with them) as these are the foundation of the food-chain and without them there would be no higher life forms. Maybe the particular cemistry of the waters there tends to select micro-organisms that are less likely to behave as pathogens?

[Kyla]

I agree, I just change the water cuz the proof is in the pudding interesting thought about the different types of pathogens, too

[adrian31@outlook.com]

As a newcomer to discus I think the main thing is that changing a lot of water and often has proven to work while other alternatives seem to fail in providing the same results. Knowing why would be interesting but probably of scarce practical use as chances are that changing water is always going to be easier/cheaper than intervening on the actual cause whatever it/they may be. Regarding the bacteria in the Amazon basin I had a look at some research papers and bacterial counts in the water are just moderately lower than in other relatively unpolluted waterways elsewhere. It would be surprising if the waters were practically sterile, devoid of bacteria (and the viruses that go with them) as these are the foundation of the food-chain and without them there would be no higher life forms. Maybe the particular cemistry of the waters there tends to select micro-organisms that are less likely to behave as pathogens?

Could the bacteria found in their waters be a strain(s) specific only to that region? It would be interesting to have a home right on the Amazon and use water straight from the river in a Discus tank. But then their clean water is also naturally replenished at a gazillion gallons per hour so there's that too.

[warblad79]

IMO, The reason why we change water so much because once all the minerals are absorb through the skin. It needs to be replenish by changing more water, that why it's ideal to raise fry from hard tap water. I raised discus ranging from 4"-7" in the same tank without issues in terms of growth.

[Neptune]

So I'll play devil's advocate...
What if they have a fresh supply of water for two years in the pool. And they've grown massive! Then a landslide damns up the supply and the pool becomes stagnant?
In other words, would nature select for this? Does nature just say I'll play the odds? I don't know??

But I do know there are lots of incidents similar to this in nature.
Often, if deer have a mild winter they will have twins in the spring. Rough winters, usually only one fawn in the spring.

Discus WC...my thoughts on why so much. Discus evolved in highly acid waters which keeps the bacteria count low. Their immune systems did not evolve to handle large and varied bacteria counts.
So they get sick quickly when exposed to high bacteria counts...just my thoughts....with maybe a little science in it? I don't know?

[Paul Sabucchi]

Once more I think that saying that the waters in the Amazon basin being acidic have very little bacteria may be not entirely correct. As an example this paper showing results of sampling of a large area of the Rio Trombetas (prime discus territory) shows an avarage bacterial concentration of 4 million bugs per ml. https://www.ncbi.nlm.nih.gov/pmc/art...8/#!po=40.1163
On the other hand it is empirically evident that their immune system is not that hot, as proven by all the problems derived from bacterial crosses so maybe either the bacteria in those waters are less aggressive or the discus that are naturally selected there are the ones that do develop an immunity to that restricted range of bacteria (but still incapable of fighting off different kinds of infectious agents)

[rickztahone]

I was just chatting with a breeder who has enlightened me as to why I change so much water. The theory is that juvenile Discus constantly secrete a growth inhibiting hormone. This is an evolutionary survival trick. If a group are trapped in a small body of water after the wet season then the hormone builds up and they do not outgrow the limited space/food supply. If they are in strong flow the hormone is washed away and they are free to grow to their full potential.
This is why we are changing water even though the fresh water tests exactly the same as the tank water! We can't test for hormones...I can't anyways.
Seems to make sense to me, what do you think?

OMG, I can hear John now....

WC's are performed for a simple fact, messy food/lots of waste/minimize organics. Simple, straight forward, and accurate.

[Clawhammer]

If you don't change discus water, not only will they stunt, they will get sick and die. It seems to me if the hormone was the issue it wouldn't be accompanied by pimples, fin rot, and bacterial infections. I think it is a myth that people want to believe because it is a simple answer to a complicated question.

[adrian31@outlook.com]

If you don't change discus water, not only will they stunt, they will get sick and die. It seems to me if the hormone was the issue it wouldn't be accompanied by pimples, fin rot, and bacterial infections. I think it is a myth that people want to believe because it is a simple answer to a complicated question.

I put it down to they're simply not adapted to other conditions. On the other hand, if through the years Discus had been bred to more robust instead of for their beauty, I'm sure they would be much more resistant to sub-par water conditions. But they would also look much different of course and we wouldn't be in this hobby.

[smsimcik]

OMG, I can hear John now....

WC's are performed for a simple fact, messy food/lots of waste/minimize organics. Simple, straight forward, and accurate.

If you're referring to Nicholson, he won't say anything. He hasn't been around here in months.

[zhuls1]

I was talking to a marine biologist about it, he told me that dissolved organics are what limits fish growth.