This is not true, while it is widely known to science that fish secrete growth hormones, numerous studies have failed to find any growth inhibiting chemicals.
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I respectfully disagree.
With the exception to the statement
"numerous studies have failed to FIND any growth inhibiting chemicals".
This a quote from Jack Wattley on GIH(Growth Inhibiting Hormones);
JacKWattleyDiscus
06-06-2002, 08:39 PM
Hello Matt
The GI Toxin or Hormone has been in play for the longest of times. We have run physical experiments sometimes planned others accidentally. Each and every time the smaller fish in the tank even from different strains have just fallen behind and become stunted. Hobbyists today always call the hatchery asking why their smaller 3" discus aren't growing as big as their 5" single fish after 1 years time.
The experiment is being experienced by all who are mixing different size fish every day and don't know that the GIT exists. And no you cannot remove it by doing water changes. I do those on a daily basis and it does not help.
If more true scientific research was placed on the discus community, so much would be revealed. Without the scientific proof we have to accept the results and theorize on the why's.
Can you immagine one little scientific experiment that told us that by adding a little something to our tanks it would diffuse it. :
Whishfull thinking.
To shed some light to the rest of the hobbyists, try to purchase and maintain all the discus in a tank of same size to avoid this problem. If you have different sizes in the same tank, get another tank. Heck that's how I did it, except that now I have 326 tanks and too much work.
Gabe
And this is where I found it;
Growth Inhibiting Hormone [Archive] - SimplyDiscus
I was un aware that waterchanges make no difference,but it actually makes senses.
The only way I saw a "late bloomer"(over 6 months old easy) change from appearing like a female to a male was when the most dominant male was removed from the tank or the other fish.
