Date: 02 Dec 1997
From: Jessica H Rabe <r64jhr@morgan.ucs.mun.ca>
To: AQUA-L@killick.ifmt.nf.ca
QUESTION:
Does anyone know about salt water ICH (white spot disease)?
Preliminary diagnosis suggests that my witch flounder (Glyptocephalus cynoglossus) larvae have it. I know it is typically a problem with warm water systems, my fish are kept at 10 celcius, which may be why only about 5-10% of my fish are affected. The white spot starts small and grows while degrading the flesh. Fish can live with it for over a month, but usually die.
I am waiting for a proper diagnosis from a histology lab, but in the
meantime I'm wondering if there are any treatments?
Jessica Rabe
MSc Candidate
Ocean Sciences Centre
Memorial University of Newfoundland, Canada
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COMMENTS 1:
From the sounds of it you may have salt water ICH (or Cryptocaryon) despite the low temperatures. You may also have a secondary opportunistic fungal infection as well. The time from infection to death which you are observing may seem long, but at the temperatures you mention, it is within reason. Being a ciliated protozoan, Cryptocaryon responds well to copper treatment (copper is not FDA approved for application to foodfish). Utilize a chelated copper and maintain copper levels between 0.15 and 0.3 mg/liter. In the past I have had excellent results with Earthtec Copper algicide, a very stable chelated form of copper. Keep a close eye on your fish for gill flaring or tetany (indicators of copper toxicity) and watch your water quality as at these temperatures the higher range of copper will affect your bio filter. Remember you will be treating the "swarmer" or "infective" stage of this parasite so at these temperatures a longer treatment period will be required. Plan on treating for 2 to 4 weeks.
If you are feeding live feeds, you may want to do water exchanges prior to feeding so as to lower copper concentrations.
If you feel you have a secondary fungal infection, or diagnosis shows the infection to be fungal, satisfy the potassium permanganate demand of the water and then add about an additional 1 to 2 ppm for fungal treatment. Perform a partial water exchange if the water maintains a pinkish color for more than 30 minutes. If allowed to persist beyond 30 minutes, your fish may begin to oxidize. Repeat this procedure every day until the infection clears up.
Michael H. Schwarz
Aquaculture Specialist
Virginia Seafood Research and Extension Center
Virginia Tech
PO Box 369
Hampton, VA 23666, USA
757-727-4861 Fax: 757-727-4871
mschwarz@vt.edu
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COMMENTS 2:
I don't know if your larvae can take this, but try a feshwater bath (w/wout formalin) for two minutes. If using formalin, bath should be stopped after the fish come to the surface for the second time.
Transfer the larvae into a new clean tank. Drain old tank and sterilize. Let air dry for a day.
Repeat this every 3-4 days until you outrace the parasites life-cycle.
You may also want to install a UV sterilizer on the water entering the
tanks.
W Douglas Crompton <crompton@hawaii.edu>
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COMMENTS 3:
We have a new preliminary diagnosis: Oodinium, according to a fish
parasitologist in our department.
We tried a 1/8,000 formalin bath for 15 minutes on the infected
fish yesterday and now 50% of those treated are dead. Perhaps the formalin is too harsh on the larvae. The survivors are not very active and may go tomorrow, while their white spots are still intact.
As for the tank dynamics...they are in a 3,000L completely flow through tank. The water is run through a coarse filter only which means that occasionally snails are found in the tank (I know that these can be intermediate hosts of fish parasites so remove them when I can). As there is no recirculation, a diatomaceous earth filter would not work, but thanks for the suggestion.
I'm looking for something mild which I can use on the fish that are
presently showing no signs of the white spot disease so that I can
effectively disinfect their tank.
Jessica Rabe, <r64jhr@morgan.ucs.mun.ca>
MSc Candidate
Ocean Sciences Centre
Memorial University of Newfoundland, Canada
***************
COMMENTS 4:
If you truly have Oodinium, a typical treatment is either moving the animals to freshwater long enough to kill the parasite while not overly stressing the animals. Another treatment uses copper sulphate usually in a chelated form in salt or hard water.
My experience with Oodinium in red drum suggests that excess nitrogen might cause "blooms" to occur overnight. Check water quality and make appropriate corrections. Oodinium is a dinoflagellate.
Since Oodinium are usually attached to the animal, I don't think u.v. or flushing of tank will directly affect them. It might improve water quality and reduce secondary bacterial infections.
Bill Daniels
Research Assistant Professor/
Extension Specialist, Aquaculture
Dept. of Agriculture & Natural Resources
Delaware State University
E-mail: wdaniels@dsc.edu
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COMMENTS 5:
We often use hydrogen peroxide. Let me know if you need
concentrations and I'll look them up.
Deborah A. Bidwell
Zooloy Department
University of New Hampshire
(603) 862-4153
dbidwell@hopper.unh.edu
***************
COMMENTS 6:
Still might be the best answer, or in conjunction w/uv, if your flow and initial filtration are sufficiently low and high, respectively, to
prevent the need for constant backwashing and recharging.
C. Greg Lutz <glutz@agctr.lsu.edu>
***************
COMMENTS 7:
I could not find your first message on the problem so I don't know what fish species you refer to. But in any case if you are looking for something mild to stimulate immunity (better then kill some concrete infectious agent by formalin), I can advise you to apply piloted photoregime for curing your juveniles. Artificial decrease of illumination causes hyperfunction of the pineal organ (located in the epithalamus of midbrain) and it produces more melatonin (important natural immunomodulator) than under natural illumination. You can simply cover your experimental tank with black polyethylene film to decrease illumination to the level of 2 - 3000 lux during one week. We've made similar experiments in the trout farm to compensate negative effects of high level of Saprolegnia sp. infection. General immunostimulating influence of decreased illumination is obtained
very quickly (1-2 weeks) and is most demonstrative in juveniles. I suppose that all infectious agents - not only fungal- could be controlled by this method.
Dr. Modest Y. Aleyev (Sevastopol, Crimea, Ukraine), <radalpin@ibss.iuf.net>
Institute of Biology of the Southern Seas
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