Growth Inhibitor Hormones and Carbon
This is a repost from another forum.....
I've noticed that while raising both trout and tropical fish fry that there is considerable range in the size and growth rate of fry within the same brood. While it is obvious that some fish feed more agressively than others and would therefore be expected to grow faster there appears to be other factors at work.
If the frequency of water changes and the volume changed is increased then there seems to be less differance in brood size and a generally faster growth rate. This has been explained by the presence of growth inhibiting hormones being released by fry and fingerlings to retard the growth of their siblings and the competition for food as a result. I have found a lot of info on the .net about research into growth hormones in fish but nothing on how to remove them. If your raising fry, you dont want anything to slow them down.
The problem is that when it comes to hormones, a little goes a long way. I read once that animal sensitivity to testosterone works at a level of concentration equal to dissolving a single granule of sugar in an olympic sized swimming pool! To remove the effect of GIH completely, you would need constant water changes.
This brings me to the carbon question: Will good quality activated carbons remove GIH from tank water and if so, how often will it need to be changed?
This is a repost from another forum.....
I've noticed that while raising both trout and tropical fish fry that there is considerable range in the size and growth rate of fry within the same brood. While it is obvious that some fish feed more agressively than others and would therefore be expected to grow faster there appears to be other factors at work.
If the frequency of water changes and the volume changed is increased then there seems to be less differance in brood size and a generally faster growth rate. This has been explained by the presence of growth inhibiting hormones being released by fry and fingerlings to retard the growth of their siblings and the competition for food as a result. I have found a lot of info on the .net about research into growth hormones in fish but nothing on how to remove them. If your raising fry, you dont want anything to slow them down.
The problem is that when it comes to hormones, a little goes a long way. I read once that animal sensitivity to testosterone works at a level of concentration equal to dissolving a single granule of sugar in an olympic sized swimming pool! To remove the effect of GIH completely, you would need constant water changes.
This brings me to the carbon question: Will good quality activated carbons remove GIH from tank water and if so, how often will it need to be changed?
