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Ich correction,
"David Thomas Gauthier" <> wrote: <<<<Subject: Ich correction (...)
Actually, this is only true at lower temperatures (<15C). (...)At
standard tropical planted aquarium
temperatures (24-26C), Ich will complete its life cycle in 3 to 7 days.
If
treatment is kept up for this period of time, all theronts will be
subject to
treatment and thus killed. No "arrested development" stage will be left
behind. (...)>>>>>>
Thanks for your comments. What I wrote is based on the wording of
Untergasser in The handbook of Fish Diseases, which mentions a
temperature-dependent maturation speed in general for the parasite and
specifically for tomites. However, in the explanation of the picture of
the parasite life cycle he mentions a cyst maturation latency time of
"up to several weeks", without reference to temperatures. I have a
foreign edition of the book, but it does not look like a translation
issue.
In fact, in Discus Health (TFH editor) Untergasser states that cysts can
remain dormant in an aquarium for months, and will produce swarmers "at
irregular intervals" (page 312). Considering the minimum temperature
requirements of Discus, the author either forgot about the effect of
these conditions on maturation speed, or used different (maybe
outdated?) references than yours. What do you base your statements on?
Another point, on the theoretical side: in terms of maturation time,
there is probably a sample mean from which the data you used are
obtained, and some variance around it. A few "late outlayers" may be
enough to maintain infectivity: are you sure that the data you provide
apply to 100% of the parasite population?
On the other side, the Manual of Fish Health (Tetra Press, page 167)
states that leaving an aquarium fish-free for >7 days at 68 deg. F
usually eliminates the pathogen, which sounds consistent with your
point. Well, I see that vets are not any better than physicians....!
I do not have reference books other than those written at hobby level:
do you have reference to veterinary texts and publications? If so, do
you mind if I contact you off-line for some info that I need?
In practical terms, the list member that we are both tying to help
stated that he does not want to use a heater, and it was not my intent
to argue against his decision. I would use it, but if he can't, that's
it! So, to be better safe than sorry, I still feel that some form of
pharmacologic treatment of the plants that he may pull out of the
aquarium may be beneficial, unless there is a way to prove that
Untergasser was wrong (maybe he was, I just cannot verify that). One
last point: maybe these guppies have been infected in the new aquarium
by the pre-existing fishes, which may have been carriers of a
sub-clinical infection. This hypothesis would not change anything in
terms of treatment options, but it should be considered in terms of
explaining what happened.
Neil Schneider <pacneil at home_com> wrote: <<<There used to be a web site
by a vetinarian, with the whole story of
freshwater ick and the cure. However I can't seem to find the URL, using
several search engines. >>>>>
Is it:
http://www.vet.uga.edu/mmb/ich.html ?
Dionigi