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

[Barry Cooper <bjc3 at centurytel_net>]

Now you are drifting away from your original suggestion, that vit. D 
influences skin color. As some of us have stated, probably not.

In humans, as we all know, sun exposure can cause pigmentation of the 
skin to develop (the suntan). However, I know of no evidence that other 
vitamins are influenced by sunlight. It is also a long stretch to guess, 
by analogy to human tanning, that sun exposure directly causes skin 
pigmentation to develop better in fish. In fact, I am not even aware 
that other mammals can "tan". For example, dogs with white bellies that 
like to expose themselves to sun don't develop a "tan", but they 
certainly do develop skin tumors as a result of excess UV exposure, just 
as humans do.

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. However, I would attribute that to a 
whole variety of dietary factors, most unidentified. Presumably some of 
these provide precursors for skin pigments that we cannot provide in 
captivity. Pond raised fish would have similar advantages. They eat all 
sorts of insect larvae, etc. that we cannot provide indoors.

Barry

Barry J. Cooper
Sweet Home, OR 97386



Koran, David HQ02 wrote:

> Bob,
>
> A couple of clicks did lead me to a melanin reference.  I am not saying that
> vitamins create the colors but probably are more related to the vividness of
> the colors, enhancing pigmentation if that is possible.  Most killies have
> the expected color patterns but "conditioning" provides one with better
> specimens.  I would say that sunlight (and hence something akin to vitamins)
> has a factor in all of this, however, is this primary or something that
> hasn't received much study.  I don't see a market SPF 15 creams for fish but
> tanning beds, maybe...
>
> From: "Robert Goldstein" <rgoldstein at rjgaCarolina_com>
> Subject: Re: [Killietalk] RE: Role of vitamins in fish color
>
> I don't know of any relationship between vitamin (or provitamin) D and fish 
> colors. The pigments I know of are melanins, pterins, and carotenoids. 
> Guanine crystals polare light reflected off the deep melanin layers to 
> reflect blues and greens through the guanine crystals.
>
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>  
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