a few comments from the friendly neighbourhood
biochemist/geneticist
On 3 Aug 2000,, Simon, Dan wrote:
> However, this male has a one gill
> cover completely missing. I thought I read that this could have been
> caused by environmental conditions, is this possible?. If it is
> hereditary and I allow the male to spawn, will the trait (or lack
> there of) be passed on to future generations ?
pH fluctuations combined with crowded and/or unstable water
conditions (especially in regard to Ca and Mg) can cause such
deformities. When I first started breeding angles I used tanks
which were too small and unstable and got lots of youngsters with
missing gill covers (opercullum) and bent fins. So, it is quite
possible that this is an environmental problem.
What evidence is there? Firstly, you say it is only one gill. If this
was an genetic trait the odds are both would be malformed. Further
more the fact that only one fish is effected would indicate that it is
not a recessive genetic disorder. If it were one could expect a
higher proportion of deformities.
However: this could be a multifactorial disorder and the reason why
it has only showed up in 1 fish is because he has all the mutations
needed to cause this. If your fish are not inbred this is unlikely
though. Further more, as fish don't have sex chromosomes this in
all likely hood isn't a mosaicism.
I would say keep the male and breed, but if you keep getting
deformities and there frequency increases cull the lot. Just make
sure you have a back up line from which to breed so keep a few
healthy youngsters back from this brood and possible get some out
side stock from another blood line.
Tyrone
http://www.geocities.com/tyronegenade/intro.html
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"Submit to God and accept theword that he plants in your
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