growth inhibiting hormone and UV

[jesse]

Hello everyone,

I wonder if someone has proof or knowledge of "growth inhibiting hormone" that affect the growth of Discus? (Discus secrete "growth inhibiting hormone" all the time, and when the tank is crowded or water changes are not often enough, young Discus have a very low growth.. that's the theory)

In the new book of Oliver "Discus Fish, a complete Pet owner's manual", he mentioned that activated carbon is removing "growth limiting hormones".
A lot of people don't agree with using carbon, and I am one of them. (that is an other subject..)

But do UV sterilizer can destroy "growth limiting hormones" as well ?

thanks,
Jess

[Carol_Roberts]

I'm not sure "growth inhibiting hormone" exists. Rather I think it more likely high bioload is the culprit. You can pack lots of discus together in a tank and still get good growth by doing 200 - 300 % daily water changes.

[CARY_GLdiscus]

How can a growth inhibiting hormone effect your Discus if Your changeing Your water?


I agree with carol!!!!!!!

Uv is not needed either!!!!!!

[wildthing]

Please explain what organ a Discus has that could produce such a hormone or pheromone, how it could possibly work in the Amazon, given the vast amounts of water there where Discus evolved, and what possible evolutionary function it would perform.
*** is this Oliver person?
only one thing worse than no information and that is wrong information.
just my $0.02
:)

[CARY_GLdiscus]

YOU GO DW!

[jesse]

I don't know if "growth inhibiting hormone" exists or not.

What I do know is that Jack Watley and Oliver Lucanus seems to agree that it exists not only in Discus but also for every fish and even plants.

I just wanted to know if anybody did some experiment to test it ?

Jess

[CARY_GLdiscus]

Jess

Not a good test Because I w/c Daily!

However I have grown out many 2" discus that were mixed in with adults without any ill effects.

I also believe more about Pheromones then GIH.

hth
Cary Gld!

[wildthing]

Jacj Wattley will vehemently tell you that he NEVER said 'HORMONE', he only used the word ' FACTOR', the factor, as Carol indicated , is already well known, NITRITES. I have spoken with JW directly about this. If you do too then you will hear a normally placid and quiet gentleman get quite agitated.
:)

Lucanus wrote a book on discus now?
oi vai!

[jesse]

I think you mean nitrate.
That may be the main cause of slow growth, I agree with that.
And that, without a heavy planted tank, there's only regular water changes to get it under control.

Do you know what is the acceptable level of nitrate for good growth ?

By the way, what is the normal growth of a Discus ?

Jess

[wildthing]

ammonia( NH3)-nitrites(NO2)-nitrates(NO3)
:)
nitrates are fairly harmless but need to be removed by w/c unless you are using a nitrogen reactor or an algae scrubber.
hth

[wildthing]

ammonia can be lethal at .07ppm, nitrites at 15ppm. nitrates are relatively safe below 35ppm. This is the premier reason for w/cs
:)
Rays, my current fishy obsessions, will sometimes get ammonia toxicity during shipping. The ammonia causes kidney damage as well as gill burn. The kidney damage kills them slowly about 2 weeks later. I suspect this also happens with discus, but that discus are not as sensitive as rays and their growth is affected.

[ShinShin]

In a talk, and in an article JW refers to a growth inhibiting toxin. True, he never said hormone, and has said so various times. The word hormone found it's way into this same discussion some years back on another forum. We are not talking NITRATES here either.

If a toxin does exist from excretions from dominate discus, it is not a stretch to believe it is a hormone. Hormones are responsible for almost all reactions of the body. Even the urge to take a crap after you eat is brought on by a hormone.

Could it exist or not is the question. No one has convinced me it doesn't and there is anecdotal evidence that it may. Chemical reactions in the body are a complicated and above the grasp of most people reading the topic at hand. Opinions are of no consequence here either, since no one (or very few) has a grasp of the concepts involved.

Hormones, being organic, ought to be removed by activated carbon or other resins available.

Discus do not live in the Amazon River.

[Terrybo]

Wildthing -

Wattley may have never said hormone, but read page 34 of the 1985 edition of "Handbook of Discus" by Jack Wattley and he talks about how some hobbyists start with fish the same size, kept in the same tank, and one gets significantly larger than the others. If nitrate was the problem, wouldn't all the discus stay small? Wattley says "It is a known fact that frog larvae release a substance into the water that inhibits the normal growth of other tadpoles in the same water". He then goes on to suggest that "Possibly this is the reason that one young discus can outgrow all the others in a tank, . . ." I suspect if I pulled my old issues of Tropical Fish Hobbyist magazine, I would find similar comments in some of his old columns. (Wattley also adds that this happens with hobbyists rather than breeders because breeders do frequent large water changes).

Terry

[jesse]

It would be nice is someone with a planted tank and low nitrate can tell us if any young Discus mixed with adult give a slow growth rate.

Anybody on the forum with a planted tank and doing one water change a week ?

Jess

[Terrybo]

If you look at what Wattley wrote, he is not talking about keeping adult discus and young discus together, he is talking about an occurance where one juvenile outgrows all others. (Based on the tadpole analogy, he would be implying only juvenile discus might release this substance). So the real test would be a planted tank of juveniles with infrequent water changes! But you would have to have a control group of fry from the exact same batch kept in a BB tank with daily water changes to get an idea of how much size varies because of genetics, versus this possible "substance".

Terry

[Carol_Roberts]

Pecking order also plays a part. Some fry are simply faster, bigger and eat more, therefore they grow bigger.

[ShinShin]

Actually, the theory is the dominant will release GIT/GIH to keep its dominace intact in its own world. If the dominant fish is removed, another will take its place, repeating the same process. If all discus are removed except the stunted discus and juvenile discus are added to the enviroment, the "stunted" discus will now be the dominant, emitting the GIT/GIH.

[wildthing]

Have you ever heard of Occams razor?

http://pespmc1.vub.ac.be/OCCAMRAZ.html

Occam's razor is a logical principle attributed to the mediaeval philosopher William of Occam (or Ockham). The principle states that one should not make more assumptions than the minimum needed. This principle is often called the principle of parsimony. It underlies all scientific modelling and theory building. It admonishes us to choose from a set of otherwise equivalent models of a given phenomenon the simplest one. In any given model, Occam's razor helps us to "shave off" those concepts, variables or constructs that are not really needed to explain the phenomenon. By doing that, developing the model will become much easier, and there is less chance of introducing inconsistencies, ambiguities and redundancies.......


( such as GIT GIH, GIF)




:)

[ShinShin]

Rereading the post regarding the nitrogen cycle, ammonia (very toxic) is broken down to nitrite (Less toxic, but toxic) then further nitrification reduces the nitrite to nitrate (not very toxic at all). The reason for w/c is to remove nitrates from the water, not nitrites. There are anarobic bacteria that will breakdown nitrate as will plants. However, a planted tank would have to be overplanted and understocked with discus to make any measurable difference in nitrate levels and cannot be used as a model to prove this topic as suggested previously in this thread. It has also been suggested by many qualified persons that exposure to high levels of nitrates at early ages contributes to stunted conditions.

[jesse]

Thanks everyone for this interesting discussion.
Ok, good point here. Planted tank do not have necessary low nitrate level.

So, maybe people who are using anti-nitrate product can tell if they noticed any difference in growth ?

On my side, I found an interesting link "how to control nitrate" :
http://saltaquarium.about.com/cs/nitratecontrol/a/aa072999_3.htm

How to do your own Denitrator :
http://www.aloha.net/~hqf/indexdondenitrator.htm

I may try to create my own this week-end. (seems very simple)
My nitrate is pretty low: 8ppm, but let see what it can do..

Jess