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Ich correction

> The problem with Ick is that cysts may
> remain inactive, but vital, for several weeks. So, quarantine only (at
> least in terms of weeks) may not be adequate.
> Dionigi

Actually, this is only true at lower temperatures (<15C).  The life cycle of I.
multifiliis progresses through the following stages:  1) trophozoite --
encapsulated, feeding stage found within the skin and gill epithelium of the
fish.  2)  tomont -- the encapsulated dividing stage that falls off the fish.
3) tomite -- final stage of division within the tomont capsule.  4) theronts--
break through the capsule, and actively swim about looking for a new host to
infect.  Treatments for ich target this last, free swimming stage, as the
encapsulated stages are resistant.  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.  At lower temperatures, the life cycle will take longer to complete,
thus treatment must be maintained to kill all ich organisms as they cycle
through the theront stage.  This can be up to 6 weeks at 7C.  At over 30
degrees C, Ich can no longer complete its life cycle and encapsulated stages
will die.  This is why increasing temperature can be an effective treatment (if
your fish can stand it).  Elevating temperature can also be used in conjunction
with treatment to accelerate the life cycle and decrease the time of treatment.
 For fish or plants with narrow temperature tolerances, this is often the
preferred method.


                                    Dave Gauthier
                                    gauthie9 at pilot_msu.edu