This is not a tough parasite to kill, but you need to understand the cycle of it before attempting any sucessful treatments.  It is important to look for specific signs of this parasite.  This parasite actually starts off as a protozoa, and becomes a parasite after a period of time.

Some of the signs of infestation with Cryptocaryon irritans are rubbing or scratching against decorations or substrate.  Determine if the fish are jerking and flashing. The fish also may display breathing problems, an increased mucous layer, loss of appetite, abnormal swimming behavior, frayed fins, cloudy eyes, and of course, white spots.

This disease is usually associated with several environmental triggers. Changes in water temperature, exposure to high levels of ammonia, nitrite, or nitrate, low pH levels, low dissolved oxygen, overcrowding and overfeeding are all factors that will contribute to the outbreak of this disease.

The lifecycle of the parasite is interesting and important to understand when evaluating a treatment. The stage where the parasite is attached to a fish is called a trophont. The trophont will spend three to seven days (depending on temperature) on the fish.

After that, the trophont leaves the fish and becomes what is called a protomont. This protomont travels to the substrate and begins to crawl around for usually two to eight hours, but it could go on for as long as eighteen hours after it leaves it's host (i.e. the fish). Once the protomont attaches to a surface, it begins to encyst and is now called a tomont.

Division inside the cyst into hundreds of daughter parasites, called tomites, begins shortly thereafter. At this stage, it is like a sporozoa.  This noninfectious stage can last anywhere from three to twenty-eight days. During this extended period, the parasite cyst is lying in wait for a host.

After this period, the tomites hatch and begin swimming around, looking for a fish host. At this point, they are called theronts, and they must find a host within twenty-four hours or die. They prefer to seek out the skin and gill tissue, then transform into trophonts, and begin the process all over again.  This process may last anywhere from 1 to 3 weeks.

 Mature trophonts leave the host and tomites exit the theront/cyst in the dark (Yoshinaga & Dickerson, 1994). Imagine if you will, a fish that randomly acquires a single Ich parasite. After a couple of days when the trophont is well fed, it prepares to drop off its host but waits for the environmental trigger of darkness. Meanwhile, the fish prepares to rest in its favorite hiding spot in the aquarium; the same fish occupy the same spot practically every night. Now, the trophont leaves the fish, encysts, and begins to multiply. Several days to weeks go by and that same fish returns to its same spot at night, only this time there are hundreds of infectious theronts seeking out a host/victim in the same area.  Only 5-20% of the theronts succeed in finding a host, but this will still add up to a large amount of infectious parasites in your tank.  The amount of parasites can increase by 10 times in 1 week.

Isolating new fish is the best way to prevent this disease from entering your aquarium.  So, the best course of treatment is prevention. All new fish should be quarantined for at least one full month. This not only ensures that the fish are healthy, but it also gives them time to get over any shipping trauma (air flights), to get used to a new diet, and to put on weight after being neglected, medicated and moved around at fish retailers and wholesalers.


Cryptocarayon Irritans Treatment

The best treatment we offer for this parasite is Quinine Sulfate, or Crypto - ProIt works better than Chloroquine phosphate that you will see many chat room members recommend to you.  It will kill the ich at any stage of it's cycle.  But, if the ich is in the tomont stage, and embedded into your sand, or coral... there are not any medications that will help you at this point.  You will be forced to change your substrate (gravel) to remove all of the tomonts/tomites buried within it.  This can be hard to accept and afford.  You could bleach your gravel, or wash it with a pressure washer... and then later on, you will run into the same problem.

So you might clear it up with the Quinine, and then have to treat your aquarium again later on.  An entire sand or gravel change is impossible without a quarantine tank that will hold all of your fish.  An entire substrate change means that you must drain your tank and start all over again.  This is why we use a coated "white" gravel here to prevent this from hapenning.  You can vacuum this gravel and not worry about sucking it up in the siphon tube.

This is why we stress so hard that everyone with a marine tank, needs a quarantine tank, preferably with a bare-bottom or coated gravel available at your local fish store.  Use coated gravel in all of your tanks, as this will prevent pathogens that are stuck in the coral from infecting your whole tank later on.  This will also prevent certain medications from being absorbed into the gravel with toxic results (like copper poisoning).  I have not had copper work for cryptocarayon or many other pathogens in the last 5 years.

Best regards,

Dr. Brian G. Aukes; PhD.
Chief Pathologist, National Fish Pharmaceuticals


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