Well Mr. Enquiring Mind - Because the number of eggs or fertility is low it
takes a while to get a reasonably number of fry. If you are using the same
rasing tank as the bigger fry get bigger they start eating the smaller ones.
So to raise them all you need a series of hatching tanks to accommodate the
different sizes. However, I don't have the tank space to have a dozen or
more tanks for raising one species of fish. In theory having 30-50 adults
will give you sufficient fertile eggs (hopefully) to get the required number
of fry all at the one time.
See, its all very simple ;-)
Adrian.
BTW Doc, you might be interested in the following piece of startling
information I come across?:
The concept of sexual selection was first presented by Charles Darwin to
explain the existence of traits, seen primarily among male animals, that
appear to contradict natural selection. Such traits include, for example,
the exaggerated tail feathers of male peacocks and the large horns and
antlers of many artiodactyls. The evolution of these traits is difficult to
explain using natural selection; the tail of peacocks presumably increases
their risk of predation, while the large horns of a ram are energetically
expensive but serve no obvious purpose with respect to survival. Darwin
suggested that such traits arise by means of a second form of selection,
sexual selection, which results when individuals (usually males) compete for
reproductive access to the opposite sex. He identified two forms of sexual
selection. Intrasexual selection involves fighting or other aggressive
interactions between males, as well as the development of elaborate
structures to serve as weapons. This mechanism for the evolution of
exaggerated male traits is generally accepted by evolutionary biologists.
The second form of sexual selection suggested by Darwin is intersexual
selection. Darwin observed that sexual selection is often driven by female
preference for particular males within the breeding population, creating
variability in male reproductive success. He proposed that competition among
males to attract the attention of females leads to the elaboration of
structures or behaviors that attract females, and assumed that females show
a sexual preference for males exhibiting a particular type of ornamentation
or behavior.
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Adrian R. Tappin
"Home of the Rainbowfish"
http://www.ecn.net.au/~atappin/home.htm
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