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Ick remedies

> Date: Thu, 25 Sep 1997 13:22:57 -0400
> From: "Maladorno, Dionigi" <DIONIGI.MALADORNO at roche_com>
> "A. Inniss" <andrewi at u_washington.edu> wrote: <<<<Subject: Re: Ick
> remedies/malachite and copper
> (...)	Also, although I have yet to run across any scientific
> documentation in support of this theory, supposedly the free-swimming
> stage of our favourite protozoan requires light to survive, so
> completely
> shutting out light to the tank for a week should wipe out Ich. I find
> the
> idea of a protozoan needing light more than a little strange, but since
> I
> have seen this advice offered by persons whose opinion I generally
> trust,
> so I am not as skeptical as I might otherwise be. >>>>>
> You are right. Reducing light has been advocated by some as a support to
> treatment of Oodinium (Velvet).I can't exclude it was advocated for
> other parasites as well. Light supports in some parasites autotrophy,
> which from what I understand enables some organisms to synthetize their
> own nutrients from simple molecules(?? am I correct in this
> definition?). I found only one reference (second hand, I did not read it
> myself): van Duijn, Jr C; Diseases of Fishes, ed 3, 1973, Springfield
> Ill., Charles C. Thomas.

Oodinium which causes velvet disease is a dinoflagellate, technically 
a kind of algae (Chrysophyta?), and it can indeed photosynthesize.  It
doesn't seem unreasonable that darkness would be detrimental to it, and
give the fish the upper hand in fighting it off, but as far as I know,
ich is caused by a protozoan with no photosynthetic capability, so if
darkness actually works as a treatment, there must be some other mechanism.

Has anyone here used darkness as sole treatment for ich?  What was the
result?  How about using darkness as sole treatment for velvet?