Causative organism: Ciliated protozoan parasite viz: Ichthyophthirius
multifiliis
Synonyms (alternative names): Ich, White spot, salt-and-pepper disease.
Geographic distribution: World wide.
Water type: Fresh water.
Typical signs of infection: Ichthyophthirius
multifiliis.
Water.
Elevated Ammonia levels, high Nitrate measurements, & sudden changes in
Temperature especially a fall in Temperature can bring about a latent infection.
Behavior. Anorexia, (loss of appetite
with consequential wasting), hiding abnormally, rubbing & scratching , breathing
at the surface, fast respiration, refusing all food are all typical indications,
but these are also signs in other problems so diagnosis must be coupled with
other indications.
Fins. Fins
folded, Fins showing white spots about 1mm in size.
Body. White spots from .2mm
- 1mm in size will appear over the body.
Eyes. Eyes may appear cloudy.
Gills. Gill examination may show
numbers of such white spots.
Skin. (smear).
Should show ciliates if white spot is present.
Life cycle & method of
transmission.
White spot, is a parasite
that covers the entire globe, & there are few Aquarists that have not met it on
one or more occasions. A sudden chilling of the fish, which can easily occur
when they are being transported from the shop to one's home, is often sufficient
to take the parasite from its latent state to the reproductive phase. An
unchecked outbreak will bring about a heavy mortality rate, though it takes
usually quite a number of days before such comes to pass, thus giving the
Aquarist time to take remedial action.
White
spot "Ich", is a ciliated parasite with a three stage life cycle. On the fish,
the only part that we can easily observe, the form is termed a trophont,
& causes the appearance that gives rise to the popular name of the condition,
i.e. "White spot". As the trophont matures it eventually breaks through the skin
(epithelial layer), & falls to the bottom of the tank, during which phase it
can attach itself to any of the various materials that we use in our Aquaria,
such as gravel, filters, airline tubing & more.
This part of the life cycle
is called a tomont. How long it remains in this stage is a
variable. Higher temperatures will accelerate its maturation, while colder
water ensure a longer latency. For this reason many Aquarists use an elevated
temperature to try and cause the parasite to mutate into the final re-infective
form termed a theront .
The parasite is at its most
vulnerable while in the free swimming theront form before it encysts as a
trophont. Various chemical therapies are effective, such as Malachite green, or
Malachite green with formalin. The Theront stage is very sensitive to higher
temperatures, which is the reason that many skilled Aquarists often try
eliminating an outbreak, purely by increasing the temperature
by some 5-80F while the infestation is endemic.
Prognosis:
If diagnosed early and
effectual treatment is applied, the outlook is excellent. However if the
infestation is at an advanced stage, then mortalities must be expected. Any
treatment method must take into account, both the species of fish (some will
not tolerate the more popular medications, see below), as well as how heavy the
infection rate is. Diligent observation of these criteria should enable the
Aquarist to obtain a successful resolution to the problem.
Treatment
The most common treatments
contain Malachite green, sometimes combined with Formalin.
The dosage will vary
according to the manufacturer, but a typical treatment level for Malachite green
is .1mg/L of water. Formalin ranges form .25mg/L to much higher levels depending
on the combination with Malachite green or usage alone, also on whether it is
meant as a timed bath treatment of prolonged immersion. One must refer to the
instructions on the chosen medication but also be aware of the points below to
achieve the desired result. We offer Malachite Green in a 1.25 oz. bottle
which is dosed at 1 drop per gallon. We also have a
Malachite Green
Concentrate which is offered in powdered form. You simply add water (we
recommend R.O. or distilled) and then dose at a rate of 1 teaspoon per 10
gallons. Formalin-MS is another alternative we offer for treating this
parasite.
There are several cautions which must be
noted when treating ich.
1)
Some fish, especially scaleless forms such as Clown Loach,
Elephant noses, & many others, also a great many Tetras, are adversely impacted
by the use of Malachite green, or some cannot tolerate the full dosage that
others can. It is therefore essential, that BEFORE applying any chemotherapy,
that one is aware of the limitations of the chosen treatment, & if in doubt seek
some professional advice. Otherwise the "cure" could be worse than the disease.
We have seen many times, entire tanks of fish wiped out for this reason, sick &
healthy fish alike. Our product, No-Ich, is safe for all types of
fish, invertebrates and plants.
2)
Heat treatment can be highly effective, however, again there are species
of fish that will not tolerate the temperatures needed to be effective. One
such example would be White Cloud Mountain Minnows. A temperature of say 820F
or higher, will cause such fish to succumb very quickly. Additionally, ich
damages the gill tissues of the fish making breathing more difficult. The oxygen
content of your aquarium water drops as temperature increases. Care must be
taken when increasing temperature so that you do not add additional stressed to
your already stressed fish.
3)
The degree of the infection. Grossly weakened fish, will not tolerate medication
that more robust & less infected ones may. All medications to some degree, are
toxic not only to the parasite but also to the fish, it is a matter of judgment,
that can take many years of experience to know just how much of a medication to
use. The guide lines given on most proprietary treatments, can only be
considered guidelines, & the user must take into account the many variables
before making his/her call on how much to use. Again, our
No-Ich is a
much more gentle therapy for your fish but it does work a bit more slowly than
other options. If you fish already have a more advanced infestation,
Malachite Green might be a better alternative, keeping the aforementioned
cautions in mind.
It is also vital to ensure
that after a treatment has been selected & found effective to make certain
that water changes are made afterwards to try and minimize any side effects on
your biological filter as well as plants etc. Naturally if it is possible it is
better to treat in a hospital tank, and when the fish are cured to reintroduce
them to the main aquarium. This ideal situation is not always possible however.
Refs. & further reading.
C.van Duijn Diseases of Fish
. Published by Ilife books London. 1973
M.Stoskopf. Fish Medicine .
Published by W.B. Saunders. 1993
D.Untergasser. Fish diseases. Published by TFH 1989
