On Optimizing Growth of Fishes
by Robert Fenner (http://www.aquarticles.com)
What are your goals in keeping aquatic life? Status quo maintenance of your
livestock? Or are you shooting for maximized/optimized growth?
Overview:
There are several important factors that affect fish growth; some may be manipulated, others
not. Further is the question of whether and how important it is to drive an organism's size.
Introduction:
In actual aquaculture, "the controlled growth of aquatic (source) protein for human
consumption", maximizing growth against cost of feed, labor, time, filtration among other costs
is of premiere importance. In pet-fish aquarium culture a similar challenge exists at the
production/commercial breeding/rearing establishments. But what about the hobby aquarist
and pond keeper? How can they, should they make efforts to optimize or maximize growth of
their livestock?
Initial Limitations:
Consider what you cannot change or control: 1) the genetic heritage and 2) developmental
history to date of your charges.
1) Think about this; no matter what you do, your livestock will not, cannot become more or
different than what their genes will allow.
Gauging the potential of koi, goldfish, tropicals, et al. is part art, part science, and part
voodoo. In the most fortunate cases, you'll be able to check out parental stock or at least
members of the same population (brood, school, area) that may give you solid ideas of what
might be in the way of growth rate, a maximum size, conformation (very important),
color...
As an example, consider a variety of nishikigoi (koi), the yamabuki ohgon. This is a classification of single-colored, golden metallic fish that by and large grow bigger,
faster than other "types" of koi; although koi, like domestic dogs are of a single species. Also,
like canines that get bigger, ohgons exhibit larger heads, pectoral and unpaired fins as young.
A similar corollary can be made for neotropical cichlids among other groups.
Important Controlling and Controllable Factors:
1) Foods & Feeding:
I've more than touched on nutrition in previous pieces. Let's briefly re-cap.>
(1) Feeding proper foods/nutrients, (2) in palatable formats, (3) at appropriate times and
intervals, (4) in suitable quantities is critically important in optimizing growth. (5) Some foods,
ingredients, natural, biological and chemical contaminants and additives have been shown to
have negative effects.
What's a mother to do, feed them Total? At the more sophisticated end, you can study up,
experiment and optimize processes per the above criteria. For most of us mere mortals,
frequent, smaller than possible feedings, less often than absolutely possible/practical, rotating,
mixing in occasional new fresh and prepared foods is about all we can handle.
Water and Water Quality: What is this stuff anyway? Wa Wa!
This will not be an exhaustive list, but let's make some general statements concerning
parameters & ranges.
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