# [Wet Thumb Forum]-Water changes for Discus in Natural Aquarium



## Avenolpey (Jun 28, 2005)

Does anyone here keep Discus? I am wondering if the water quality of a balanced system eleviates the need for daily water changes typical of most Discus tanks. If yes, how infrequently do you get away with water changes?


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## dwalstad (Apr 14, 2006)

The only reason I can think of to do water changes is to remove ammonia, nitrites, acidity, or excessive water hardness (for softwater fish). 

If plants are growing well, then the first 3 things will be taken care of.

When I've set up quarantine tanks (without plants), the water goes bad very quickly (mainly ammonia). In these tanks, I have to change 50% of the water every 2-3 days. 

Having an established planted tank is just so nice.


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## Avenolpey (Jun 28, 2005)

Thanks Diane for your reply. I have heard that discus as well as other fish excrete growth retardent hormones, and the only way to remove is through regular water changes. Do plants or aerobic soils remove these hormones as well as the A.N.N.


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## dwalstad (Apr 14, 2006)

> Originally posted by Avenolpey:
> Thanks Diane for your reply. I have heard that discus as well as other fish excrete growth retardent hormones, and the only way to remove is through regular water changes. Do plants or aerobic soils remove these hormones as well as the A.N.N.


I'm sorry but I don't know what A.N.N. means.

I would love to see the scientific references documenting these inhibiting growth hormones. If anyone has information on what the identity of these hormones are, please enlighten all of us!

Until someone backs up their statements about inhibitory hormones with a scientific study, I will continue to be skeptical.


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## Avenolpey (Jun 28, 2005)

A.N.N. - Ammonia, Nitrites and Nitrates.

I will try to find some information on the hormones. I have only read it on other forums, and will work to get the facts.


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## dwalstad (Apr 14, 2006)

Thanks for the clarification of ANN.

Back to your original questions. If these hormones exist, I don't think that plants would affect them (plants don't take up organic molecules as food). 

However, hormones are organic carbon, which makes them subject to decomposition. I believe that bacteria, which are very active in a planted tank, would slowly digest them. Thus, a planted tank with a thriving bacteria population would moderate the level of any hormones released by the fish. How much moderation is anyone's guess.

I've raised plenty of cichlids and Rainbowfish in well-planted tanks with minimal water changes. The fish didn't appear stunted.

Finally, as hormones are organic molecules, they can be removed by charcoal filtration.

Hope this helps!


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## magicmagni (Aug 19, 2004)

> I believe that bacteria, which are very active in a planted tank, would slowly digest them. Thus, a planted tank with a thriving bacteria population would moderate the level of any hormones released by the fish. How much moderation is anyone's guess.


This is a good point and may explain why planted Discus tank folks, myself included who aren't doing the daily water changes recommended by "the Discus Experts" don't see the negatives; this alleged problem as well as the ANN issue they so fear. Not to say these problems do not exist- they do, but I'd speculate they are more of a problem in the "sterile" environments (no gravel, small sponge filter)commonly used in traditional discus tanks. Such environments can't harvest much if any beneficial bacteria I'd think.

Jeff


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## dwalstad (Apr 14, 2006)

Good to hear from a Discus keeper using the natural approach. I wasn't sure there were any.









I think bare tanks are basically unhealthy. There's no surface area for bacteria to do their business (digesting organics, removing ammonia, etc). Planted tanks with soil have a zillion times more surface area for bacteria to colonize than a bare tank with a filter.

Degradation of inhibitory hormones may be just one more asset of having a natural tank that I hadn't thought of before.


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## phishluvr (May 29, 2005)

I'm also glad to see others interested in natural discus tanks.









Since discus prefer lower light environments, it would seem better to have them in a low-light planted aquarium. I guess I'm surprised to not hear more of discus in natural setups.

Magicmagni, could you please share your maintenance routine so those of us who are looking to go this route have a better idea of what is required?


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## discusmad (Mar 26, 2006)

I know I know a nother newbe looking at an old post but to clear up some questions here in this topic

1. adult discus do produce a growth inhibiting toxin decovered by the king breader of discus Jack Wattley but they don't stunt the smaller fish just slows it down alot.....nothing like a bit of poison to keep the competition stunted, eh?

2. with my experiance discus in a planted "natural tank" grow slower even with daily 50% water changes than in a bare tank. But they do make a nice background for a planted tank

3. discus can handle very bright lights they get use to them as long as there is some "shade" for them


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## flagg (Nov 29, 2004)

The so-called hormones ya'll are referring to are called growth limiting substances (GLS) and growth inhibiting substances (GIS). Apparently these appear to be exocrine substances which have growth limiting/inhibiting effects on other fish. In general it is believed that they come from gill and anus secrestions and possibly also from body slime. 

See this link for a more detailed and scientific discussion on the matter (along w/ referenced articles for your perusal, Diana!).

See also the FAQ linked to at the top of the above-referenced article as well as the other articles mentioned under "See also Articles on:" All of the aforementioned provide a wealth of information on the subject.

-ricardo


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## Matsvin (Apr 17, 2006)

I've actually read a scientific study about something that fish produce that stops growth and reproduction or something like that. Sorry that I can't remember the details, this was before 1980... The study just tested IF fish do it, and found out that they did. The species tested was guppy & Tanichthys albonubes. The study did not test what it was that the fish produced. The scientist was into etology, I believe. If I ever find it again I'll post the info.


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