Fwd: factors relating to growth

["Ed Pon" <edpon@hotmail.com>]

>I seem to have better luck with growth if the fry remain in the tank of 
the
>parents (gravel, plants) than if I transport them to a bare tank of the 
same
>gallonage.  Perhaps it is the parenting, but it could also be the 
availability of
>small food in a gravel-based and planted  tank.  Another possibility is 
the
>bacteria action in the non-bare tank.  Do the bacteria remove some 
hormones or
>toxins which can build up in the bare tank?  I'd add this variable as 
something
>to be investigated.
>
>I have occaisionally noticed problems with growth in either set up 
after the fish
>reach a certain size.  Perhaps I'm just underestimating the amount of 
additional
>food 1/2 fry need compared to 1/4 inch fry.  After all, doubling length 
probably
>quadruples body mass.
>
>--Randy

I don't recall seeing this behavior in Apistos, but convicts will use 
their "chests" to bulldoze some of the gravel and stir up food particles 
and maybe small critters in the gravel for their fry to eat. I think the 
fry grow faster with the parents because of this help.  Most aquarists 
don't have the time to constantly dump food into the tank whereas the 
parents are constantly herding the fry around the tank seeking the best 
grazing areas.

I have noted the slowdown in growth when fry get to a certain size and I 
wonder if it is attributable to the anti-growth hormone theory.  There 
is a theory that some cichlids emit anti-growth hormone that cause fish 
of the same species to slow down in growth and even get sick.  The 
theory is that this is survival-enhancement for drought periods when the 
pools of water may be smaller and food is less abundant.  I wonder if 
increased water changes at this stage or lessening the amount of fish in 
the tank may help.  In raising bearded dragons, a type of lizard, the 
intimidation from some of the faster growing lizards seems to stunt the 
growth of their cohabitants whereas if the lizards were raised 
individually, they all have roughly the same growth rate.  Perhaps 
intimidation from certain individuals in the growth are slowing down the 
growth of others because of stress and the inability to eat more because 
of bullying.

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