Re: [RML] Methylene Blue

Wright Huntley (huntley1 at home.com)
Thu, 29 Apr 1999 21:14:19 -0700

Gary Lange wrote:
>
> Do you use this mix (acriflavin) on your rainbowfish eggs or just your
> killifish eggs??

Mostly killies, but puddlefish tend to be puddlefish. :-) As I said, I
*don't* use it in anything but extreme cases.

> I didn't obtain very good results using ANY amount of
> acriflavine with rainbowfish eggs.

Used alone, or too strong, I have the same experience (rainbows *or*
killies). Acriflavin, like "Formalin" is just too agressive and ruins
more eggs than it saves, IMO. Some Aphyos and Epis seem more tolerant.

> It had worked quite nicely with
> killifish for me until I advanced :-) to the peat spawning killies and then
> it became unnecessary. There was a vet 2-3 years back in TFH that said that
> methylene blue really served no purpose except to darken the water and cut
> down on the light.

*Any* analine dye tends to act as a cross-linking agent to "tan"
proteins. That bothers mobile bacteria more than fungi, apparently.
Otherwise, I think he's right on.

> Do you have any references for methylene blue being an
> anti-bacterial?

Not in the true scientific literature. It may *be* there, but my input,
as I recall, was verbal from a vet pathology prof who is also an
aquarist. See p 128 of Untergasser's _Handbook of Tropical Fish
Diseases_ (TFH) for a "Spectrum of Action" list. I don't think it is
anywhere near complete, tho.

> I have found the best use for methylene blue is when I want
> to find which eggs are fertile. Infertile eggs will stain a very dark blue
> where fertile eggs will exclude the dye. If you don't overdo the MB it's a
> good way to quickly tell the difference. I don't add anything to my hatch
> water tank and have fine hatches. I usually put the mop into a tank with
> freshly dechlorinated tap water though so there aren't a lot of bugs to
> cause problems. Sometimes I think that people end up with a lot of fungus
> in their eggs because their males are shooting blanks or not driving the
> females hard enough. Then they blame fungus. If you think this could be a
> problem try picking a few eggs and putting them in a shallow tray of MB. If
> they all turn blue then you've got troubles with your male.

They tend to turn white, quickly, anyway, if not fertilized. [Tough when
dealing with anabantids where the eggs are often creamy white to start
out! :-)] If the water is filthy, the fungus will start to appear as
soon as they turn white, tho. I have kept infertile (at least
non-developing) eggs for weeks in a weak (very pale green) solution of
acriflavin and methylene blue, without ever seeing any fungus develop.

Fungus grows on necrotic tissue. It is, IMHO, almost never a primary
infectious agent. I believe bacteria must break down the chorion for it
to attack dead eggs. That's pure opinion, but based on some years of
observation and tinkering.

I agree, strongly, with Gary that the dye will selectively color the
dead eggs. At that dye level, tho, many live eggs will never hatch (in
some species). I'm a lot more cautious with it, now.

Wright

-- 
Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot
com

Stop passing new laws! Repeal some dysfunctional ones. It will do far more good.* http://www.self-gov.org/libertarianism.html ________________________________________________ *Substance-abuse laws and other victimless-crime laws for example.