Re: mineral uptake

[Mike & Diane Wise <apistowise@fgn.net>]

Zack,

You are probably right. As I said "little if any" minerals get through the
osmotic defenses of soft water fish. Graham Rowe (you Aussies know the
gentleman, I'm sure) told me about 20 years ago that he used crushed coral in
his trifasciata tank because so many fry would turn up as belly sliders or with
curved spines. It may have worked for trifasciata, which can handle higher
hardness values but I doubt it would encourage spawning in blackwater species.
Whether or not discus are different, I don't know. I understand that most wild
discus come from clearwater biotopes (slightly acid & very soft) and are as
adaptable as apistos to water conditions. In fact most domestic forms can even
handle moderately hard alkaline water. In harder water conditions the
concentration of minerals are higher (duh!) so the likelihood of minerals
passing the fish's osmotic barrier is better. The advantages for a discus (or
apisto) breeder in using harder water is probably more for acclimating the fish
for the average aquarium than adding any mineral content.

Mike Wise

Zack Wilson wrote:

> I think both sides of the issue can be and are correct. In nature the fish
> (discus or Apistos) obviously are not getting their mineral needs met from
> absorption from the water, yet they grow and develop without problems, at
> least no more than normal.
>
> Yet when we breed them in captivity we can sometimes observe problems with
> growth and development with our fish. This problem was discovered to be
> correctable with the use of mineral rich water. Is it possible that the fish
> are adaptable enough to take advantage of the minerals in the water to
> compensate for a lack of mineral content in their diet where they would
> normally obtain these nutrients. I'm sure we have yet to perfect our foods
> for our fish and may be lacking all the necessary ingredients. Our water's
> buffer really helps in more way than one! Maybe?
>
> Zack
>
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