Re: [RML] sex reversal was Male or Female Kubutu Rainbowfishes

Adrian R. Tappin (atappin at ecn.net.au)
Fri, 20 Mar 1998 08:05:03 +1000

At 00:01 19/03/98 -0700, Julie wrote:

>snip,snip.

>Hope this helps some. You may also want to know that I do not usually pull
>out the lunkers, so some of the difference *may* be due to cannibalism by
>the larger, faster growing ones (males?) on the runts (females??). Just a
>thought. I have a sm batch of 6 now and they are beginning to look like
>mostly gals, but are still small yet.

Personally, I think its probably temperature influenced as Gary mentioned. I
was reading an aquacultural article (still in press) and it mentioned
temperature "in passing" but didn't go into details.

some extracts:

"Sex reversal is the manipulation of the fish either with the use of
hormones or temperature to drive a population towards being completely one sex"

"The sex of an animal is determined by one of two methods:
1.Sex determination occurs at the time of fertilisation, when the
chromosomes from the male and the female join forming a zygote.

2.Sex differentiation occurs as the larvae is developing and there are
bundles of cells in its body that become various organs. The differentiation
into either male or female occurs as a group of cells are developing into
gonads."

Does anyone know when the sex of rainbowfishes is determined.

And I don't want any funny answers Bruce! - although 'tongue in cheek'
answers would be alright ;-)

Adrian.


...............................................................
Adrian R. Tappin
"Home of the Rainbowfish"
http://www.ecn.net.au/~atappin/home.htm
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