RE: [Killietalk] RE: Role of vitamins in fish color

[Brian Watters <bwatters at sasktel_net>]

>
> There is no argument that the colors of fish are better appreciated in
> natural sunlight. Try looking at a blue N. eggersi sometime in natural
> light! I also do agree that wild fish typically have more intense
> coloration than tank raised fish.
>

There is no question that, in general, wild fish have a brilliance of color
that one rarely sees in captive-raised specimens. However, that is not
always the case with Nothos - every now and again in the field one will
encounter a pool where the Nothos are almost completely devoid of color and
this is a phenomenon that I have no clear explanation for. We have found
cases where, for example, male N. kirki and N. melanospilus were completely
devoid of color and were simply plain white fish, perhaps with only a hint
of blue iridescence on the body. Even the black spots on the female N.
melanospilus were mostly invisible. The only common factor that I have
noticed in pools where the Nothos show this is that the water had a very
bright milky-white turbidity. In the case of one of the N. kirki localities
where I encountered this phenomenon, I also collected specimens from pools
connected to a stream system, literally just a few meters away from the
milky-white turbid pool and in those the Nothos had brilliant color. Almost
all Notho habitats are turbid but will usually have a grey or brown color;
what I am referring to here is notably different, being very bright and
light in color. The specimens in these unusual habitats were otherwise in
excellent condition. I am convinced that the lack of color in the fish was,
in some way, a reaction to this quality of the water but I have no idea why.

Anyone have any "bright" ideas about this phenomenon ?

Incidentally, in all cases, when we brought the fish home, within two weeks
or less in the aquarium they had regained full and brilliant color.
________________________________________
Brian Watters
56 Gardiner Avenue
Regina, Saskatchewan S4S 4P6, Canada
Tel: (306) 584-9161 (home)
E-mail: bwatters at sasktel_net

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