In the first part of this series, I discussed some of the most common, tried and true methods for dealing with Marine Ich, along with symptoms, its life cycle and prevention. In this second part, I discuss some of the newer and/or more experimental "cures." Please keep in mind the lifecycle of the parasite and the proven cures when evaluating the effectiveness of the treatment options detailed below.

Natural Immunity

Fish can develop immunity to Cryptocaryon irritans that can last for up to six months (Colorni, 1987 and Colorni & Burgess, 1997). It is this natural immunity that makes evaluating the effectiveness of various treatment options so difficult. How can someone ever be certain that what they dosed to their tank or fed to their fish is what caused the cure they observed? The answer is simple, they can't. Until there are controlled, scientific studies, preferably repeated a few times, we cannot be sure that any of the newer homeopathic or "reef-safe" treatments actually work.

This limited immunity is also the basis for some aquarists advocating that if a fish gets sick, to just maintain pristine water quality, feed a superb diet, and to allow the fish's own immune system to do the job. While it is possible that this could work, natural immunity is not totally foolproof. In the studies cited above, some of the fish were not completely protected by their own natural immunity. It is possible that immunity could protect the fish from massive infestation, but still allow small numbers of parasites to remain and reproduce undetected by the aquarist. This is where the 'Ich is always present' argument comes into play and why sometimes an aquarist has recurring difficulties with this pathogen. It is possible, in some cases, that the treatment was cut short or misapplied or for some other reason not totally effective, but that immunity helped to partially ward off the infection. In this situation, a low-level infestation, held in check by natural immunity but not totally eradicated, could continue to survive but be misdiagnosed, or missed all together, by the hobbyist. The parasites could progress through their lifecycle by predominately attacking the gill tissue, where they could go unseen. Or, the number of parasites could be so low and their appearance (and disappearance) be erratic enough that the aquarist does not pick up on the infection or attributes the occasional white spot to a speck of sand or air bubble because the fish are behaving normally otherwise. That is until some other minor mishap occurs or the immunity wears off and the balance shifts in favor of the infestation, resulting in a full-blown infestation once again.

I want to be clear on this point. I do not believe Cryptocaryon irritans is always present in our systems. With a strict quarantine protocol, it is possible keep an Ich-free aquarium. I just believe that there have been enough hobbyists who have misused a treatment or utilized an ineffective treatment option, such that they never really fully conquered their initial infestation. Their continuing problems over the course of many months, and the posting of those experiences, seem to be enough to promote this aquarium myth. Cryptocaryon irritans can be eradicated from an infected system with a proven treatment and can be kept out of the system if good quarantine practices are employed.

Most of the hobbyists who consider letting their fish fight off the infection on their own are hopeful that it will work because they find the challenge of removing all the fish and allowing the aquarium to go fallow (without any fish hosts), very daunting. If you are considering natural immunity as a treatment option, ask yourself a few simple questions.

How big is the tank?
How difficult would it really be to tear the display apart to capture and remove all of the fishes to a separate hospital/quarantine tank for treatment?
How much is it going to cost to replace all of the fishes in the event of a catastrophic loss?
What kind of moral and ethical responsibilities do you have for the pets that you purchased?
And lastly, what in the world were you doing adding anything that had not been quarantined into your aquarium in the first place?

I cannot answer these questions for you, but it is my opinion that it is inappropriate to do nothing. I would hope for acquired or innate natural immunity to kick in when used with other less aggressive but pro-active treatments, such as using biological cleaners, medicated foods, UV, ozone, and garlic. Although I clearly don't believe this shotgun approach of unproven treatments is the most effective option available. For me, if you gamble with un-quarantined items and infect your tank, it is best to bite the bullet, remove all the fishes to a separate quarantine aquarium, fallow the tank, and use a proven treatment.

Treatment Option 6: Freshwater Dips

Freshwater dips are a highly effective form of treatment against a wide variety of parasites, although their use against Cryptocaryon irritans has been questioned (Colorni, 1985). I am including them here because I still choose to employ them, as I believe they have at least some effect against Ich and because they have been proven effective against Amyloodinium, Turbellarian Worms (the so-called Black Ich), some Flukes (Noga, 2000), and Uronema (Kollman, 2003). For these reasons, freshwater dips are still part of my standard operating procedure when receiving fish.

For some reason, many hobbyists are extremely reluctant and nervous about freshwater dipping their fish, yet show little concern about using toxins, poisons, and carcinogens, such as Copper or Formalin, for treatment. It is my contention that any fish that does not survive a properly conducted freshwater dip would not have lived regardless of treatment. I have dipped hundreds, perhaps thousands of fish, and have yet to kill a fish with a freshwater dip. I define this by the fish dying either in the dip bucket or within hours of the freshwater treatment. If a fish dies a day or two later, while one may claim it was the result of the dip, it is more likely that the disease was too far along and the fish too damaged to survive.

To prepare a proper freshwater dip, take either dechlorinated tap water or demineralized water (RO or DI), aerate for an hour to maximize dissolved oxygen, heat to match the temperature of the dip water to that of the tank water, and then add buffering compounds to match the freshwater pH to your saltwater pH. The aeration should continue throughout the dip. It is crucial to match temperature and pH and to maximize dissolved oxygen. Most people that experience problems with freshwater dipping have made an error in these critical parameters.

The recommended duration of the dip varies from author to author because different species of marine fish tolerate freshwater to different degrees. Generally speaking, any dip less than two minutes is useless. Many fish will easily tolerate five, ten, even fifteen minutes or more. The least tolerant fish are wrasses, lionfish, pufferfish, drumfish, hi-hats, jackknives, firefish and many of the scaleless fish as a rule (Calfo, pers. comm.). I also choose not to dip lionfish, foxfaces, or any other venomous fishes because I don't want a flying torpedo of spines to come shooting out of a dip bucket at me. A lionfish has stung me before, and it is not an experience I ever wish to relive.

Please only dip one fish in each bucket. If you must dip several fish, it is best to make up several smaller freshwater dips versus one large bucket, and always discard all dip water. I also would like to warn you about dipping fish that excrete toxins. There are several fish that give off toxins with their protective slime coat. Mandarins, boxfish, and the Six-line Grouper are a few. When in freshwater, they will naturally excrete more protective slime. There is a possibility that in the confines of a dip bucket, these fish could poison themselves or others, so be careful.

The best advice I can give you is to observe your fish closely. Some fish will swim around like nothing is happening. Others will go straight to the bottom and lie there. Definitive signs of trouble are manifested by the fish jumping out of the dip bucket and spitting water.

There is an alternative to standard freshwater dips that should also be mentioned. Some individuals prefer to use freshwater with methylene blue in the dip (Fenner, pers. comm.- more information here). Methylene blue is a copper based anti-microbial dye. It is effective against a wide range of microbes such as bacteria, fungus, yeast, etc. This combination works well to rid the animal of external parasites and provides some protection against secondary infections. As I stated in part one of this series, I almost always use daily water changes. These daily cleanings tend to spur the fishes' own immune system to combat any secondary infections by helping to maintain optimum water quality, so I have not felt the need for using Methylene blue, but it is a worthwhile option to consider.

I wanted to add a footnote on the effectiveness, or lack thereof, for freshwater dips against Cryptocaryon irritans. The question of whether they work or not stems from one study, Colorni 1985. In that study, Colorni watched as trophonts and their host, the Gilt-Head Sea Bream, Sparus aurata, were given freshwater dips. After the dips, which lasted up to 18 hours, were administered the trophonts were still there in their same positions. These same trophonts later dropped off the fish and reproduced successfully. My first comment is, I am unsure if any of the common ornamentals we see in the trade could withstand an 18-hour freshwater dip! Secondly, Gilt-Head Sea Bream, Sparus aurata, are found in marine, brackish, and even freshwater environments. I am concerned that whatever protection these fish have that allows them to withstand such osmotic shock could also unintentionally protect the parasite. Please take my musing with a grain of salt. Better yet, make that a whole 50-gallon bag. I am not a doctor, nor am I schooled in fish pathology. This was merely something that struck me in my reading, so I wanted to mention it. In fact, it has aroused such curiousity that I am currently working on developing a protocol for testing freshwater dips against Cryptocaryon irritans in a common marine ornamental species. I will keep you posted.

With all that I have discussed concerning freshwater dips my position on its use may seem a bit murky. Just to clarify, I do employ and advocate the use of freshwater dips when first receiving fish. I believe all fish that can be dipped should be administered this treatment prior to placement into a proper quarantine tank. This is done in an effort to minimize all possible parasitic infections. I do not, however, recommend freshwater dips as a cure for Cryptocaryon irritans. In my opinion, the repeated handling and osmotic shock of repeated dips are far too stressful to warrant its usage when other proven, but less aggressive treatments are available such as hyposalinity or daily water changes. Lastly, assuming freshwater dips can kill the embedded trophonts on a fish, once they are returned to the infected aquarium, they are just going to contract this pathogen again. So, I recommend using them and using them once only upon receiving the fish to minimize all possible parasitic infections.

Treatment Option 7: Quinine Based Drugs

Quinine Hydrochloride and Chloroquine Diphosphate are two medications commonly available, although the later is usually indicated for the treatment of Marine Velvet/Amyloodinium. Several of the references report these Quinine-based drugs as having mixed results, and I agree (Bassleer, 1996, Gratzek et al, 1988 and Fenner). I have used a commercial preparation of Quinine Hydrochloride and Malachite Green on several occasions when treating a display aquarium. In all instances, the infestation subsided, but with a few mortalities. In my opinion, I would have experienced fewer deaths with the removal of the all the fish to a separate quarantine/hospital tank.

I can say that the Quinine Hydrochloride and Malachite Green preparation is fairly invertebrate safe. Although I have never used it in a full-blown reef tank, I have used it in the presence of motile invertebrates (various shrimps and crabs), liverock, and livesand (along with the various hitchhikers; amphipods, copepods, small feather dusters, sponges, chitons, etc.) with little to no discernable adverse reactions. The only effect I witnessed was Sun Polyps (Protopalythoa grandis) turned green, although this was likely due to the Malachite Green. They did survive though, resumed their normal coloration, and have since multiplied, as did all of the little liverock hitchhikers.

I need to point out a few serious precautions regarding the use of Malachite Green. First, it is a respiratory poison, teratogen (an agent that can cause malformations of an embryo or fetus), and a suspected carcinogen. For these reasons, it is illegal to use on food fish in the United Sates, although it is still used on ornamental fish for treating eggs for mold and fungal infections. Also, Malachite Green is thought to accumulate in tissue after repeated treatments (Noga, 2000). Lastly, the original preparations of Malachite Green from the 50's were made from the mineral Malachite (Dr. Shimek, pers. comm.), which contains high levels of copper. Although the compound Malachite Green does not contain copper, it is possible some aquarium preparations may contain traces of copper and could be very toxic to invertebrates (Dr. Shimek, pers. comm.).

Treatment Option 8: 5-Nitroimidazoles

There is another class of products on the market that are alleged to be a reef-safe, alternative, anti-parasitic medication for Cryptocaryon irritans. The active ingredient of this category of treatments is 5-Nitroimidazoles. I have only used this type of product a few times, but never in a reef tank, so I cannot speak to those claims. I found these to be moderately successful against Cryptocaryon, although it required twice as many applications as the manufacturer stated on the instructions to affect a complete cure. My biggest complaint is how expensive it was, in particular accounting for the amount and time needed to affect a full cure. Anyone who wishes to try one of these products should perform a search on several of the online message boards to get additional feedback prior to purchasing. Based on my own experience alone, I cannot recommend them.

Treatment Option 9: U.V. Sterilization

Ultraviolet sterilizers work by damaging most anything in the water column that passes through them. Their effectiveness is dependent on the wattage of the unit, the flow rate through the unit, the age of the lamp, the volume of the water being treated, the cleanliness of the sleeve, the clarity of the water, and the decorations (potential hiding spots for tomonts) in the aquarium (Moe, 1989). Colorni & Burgess (1997) discuss the use of UV. They extrapolate from a previous study done on freshwater Ich, Ichthyophthirius multifiliis, and UV (If you are so interested, the original article is Gratzek, Gilbert, Lohr, Shotts, and Brown's 1983 piece "Ultraviolet light control of Ichthyophthirius multifiliis in a closed fish culture recirculation system." It can be found in the Journal of Fish Diseases volume 6 pages 145-153). In the study, they showed UV could prevent the spread of Ichthyophthirius multifiliis when used on a central system, but could not affect a cure within an individual aquarium. Colorni and Burgess believe the same would hold true with Cryptocaryon irritans. I would concur with them as my own personal/professional experience has demonstrated the same. I have found UV's to be very effective in bare bottom tanks, primarily in retail and wholesale operations. In display aquaria, the volume of the tank, the substrate and rockwork, the flow rate of the UV, and the wattage all work against its effectiveness. In commercial operations, many times, employees wipe down bare bottom tanks daily to maintain a clean appearance for customers. This has the added benefit of knocking loose the cyst stage of the parasite. The bare bottom, minimal decoration, high flow rates, and massive UV units on these systems ensure that most all the cysts and theronts pass through the sterilizer and are neutralized.

Please note that while I have drawn a comparison between freshwater and saltwater Ich, there is no taxonomic relationship. They may appear superficially similar to aquarists and they do in fact share some common features such as life cycle, mode of reproduction, and dispersal mechanism, but they are different and distinct organisms. This is a case of convergent evolution; when different organisms evolve to have a similar appearance because they occupy similar niches. There is a very nice example illustrating this phenomenon located at this website.

Treatment Option 10: Ozone

The use of ozone is somewhat similar to the use of ultraviolet sterilizers in that you are attempting to kill the pathogen by killing everything that passes through a reaction chamber. In this case, the reaction chamber is usually a protein skimmer, although there are some dedicated ozone reactors on the market and instructions on the Internet for DIY units. Ozone does not have as many of the variables affecting its performance as UV's do. On the contrary, if water clarity is an issue, ozone will help to improve overall water quality while at the same time, work towards neutralizing parasites.

The other big difference between ozone and UV treatments is there is a higher probability that the use of ozone can affect a cure in a single aquarium. Wilkie and Gordon (1969) reported that they were able to prevent the infestation of fish placed into an infected aquarium for 21 days with the use of ozone. Unfortunately, due to the prolonged life cycle of Cryptocaryon irritans, I cannot say that this is definitive proof, but it does show some promise. It was not until more recently that the biology and life cycle of Cryptocaryon irritans was better understood, so much of the older data on this disease is now deemed inconclusive.

The major drawback to the use of ozone is the potential to overdose and kill everything in the system. Ozone must be administered using a monitor/controller unit. Also, the effluent of the water and air should be run through activated carbon to ensure that any residual ozone is neutralized (Moe, 1989).

Treatment Option 11: Biological Controls

While probably not able to affect a cure in a full-blown infestation, the use of cleaner shrimp may help with a mild problem. I wish to express my dismay when seeing cleaner wrasses, Labroides species, offered for sale. The vast majority of these are doomed to waste away as they are obligate feeders of marine ectoparasites (Fenner, 2003). There are many other effective cleaners available with a much better survival rate. Please leave these fish in the ocean where they can live long, happy lives and help maintain the health of the other reef fish.

The other argument against the use of Labroides wrasses is, being a fish, they are just as susceptible to infection as the fish they are "treating." In a closed, contaminated system, the cleaner wrasse will, in time, become infected too. As a result, it will eat less and become useless for combating Cryptocaryon. This same argument also rules out the use of other cleaner fish such as the various Gobiosoma species. While these make excellent aquarium residents, they are not an effective cure for parasitic diseases of fish. The cleaner shrimp, on the other hand, are not susceptible to Cryptocaryon and could therefore help to bring about a cure, while not being a complete cure in and of themselves.

One last note on Labroides wrasses, contrary to popular opinion, they do not consume Cryptocaryon parasites. They have demonstrated a strong preference for gnathid isopods, which make up between 77 and 85% of their natural diet (Grutter, 1997 & 2000). The remaining prey items are composed of scales, parasitic copepods, and non-parasitic copepods. So, regardless of whatever conscientious objections one may or may not have regarding their availability in the marine aquarium trade, they are not going to help in the battle against Ich. Also, since Cryptocaryon irritans is known to be rare in the wild (Bunkley-Williams & Williams, 1994), it would follow that it is unlikely that Ich makes up any significant portion of any cleaner organism's diet. This, coupled with how deep the trophonts embed, throws into question the effectiveness of any cleaner against Cryptocaryon irritans.

Treatment Option 12: Medicated Foods

Tetra previously made a medicated food, Anti-Protozoan Medicated Flakes, which was reported to be effective against Cryptocaryon. The active ingredient was Metronidazole, also known as Flagyl. This was a good option when it was impossible to remove the fish to a separate quarantine/hospital tank because this food was safe for use in the display tank. The only downside was whether the fish could be coaxed to eat it at all and whether they could eat enough of it. Although the Tetra Medicated Food is now discontinued, Metronidazole is available, so it is possible to obtain it and mix it into the fish's favorite food and, with luck, to elicit a feeding response.

The medicated foods are a good option for use as a preventative, for mild infestations, or when used in conjunction with one of the other less effective treatments, such as biological controls, UV, ozone, and garlic. All of these methods could be employed together in a display tank when removal is not chosen, although this is not the most effective solution, in my experience. I have always had better luck going through the trouble of removing all the fish for separate treatment or better yet, quarantining all new livestock and avoiding infection in the first place.

There is one possible drawback to this treatment that was brought to my attention. Feeding something like Metronidazole, or potentially even garlic (discussed below), could have deleterious affects to the beneficial microflora of a fish's intestine, much like the side effects to Copper exposure (Dr. Charles Moon, aka moonpod, pers. comm.). Additionally, any medication with significant antibiotic properties will act upon the bacterial populations living in the system, and will foster the development of drug resistant bacteria (Dr. Ron Shimek, pers. comm.).

I cannot answer these questions for you. My opinion is I do not think it is appropriate to do nothing. Although, I would hope for acquired, natural immunity to kick in when used with other less aggressive but pro-active treatments. For example, using biological cleaners, mediated foods, UV and/or ozone, and garlic while hoping for immunity when treating a display tank.

Treatment Option 13: Medicated Foods

Tetra previously made a medicated food, Anti-Protozoan Medicated Flakes, which was reported to be effective against Cryptocaryon. The active ingredient was Metronidazole, also known as Flagyl. This was a good option for when it was impossible to remove your fish to a separate quarantine/hospital tank because this food was safe for use in the display tank. The only downside was whether you could get your fish to eat it at all and to eat enough of it. This medication is available besides the now discontinued Tetra Medicated Food, so it is possible for you to obtain it and mix it into your fish's favorite food to hopefully elicit a feeding response.

The medicated foods are a good option for use as a preventative, for mild infestations, or when used in conjunction with one of the other less effective treatments, such as biological controls, UV, ozone, and garlic. All of these methods could be employed together in a display tank when removal is not chosen, although this is not the most effective solution, in my experience. I have always had better luck going through the trouble of removing all the fish for separate treatment or better yet, quarantining all new livestock and avoiding infection in the first place.

There is one possible drawback to this treatment that was brought to my attention. Feeding something like Metronidazole, or potentially even garlic (discussed below), could have deleterious affects to the beneficial microflora of a fish's intestine, much like the side effects to Copper exposure (Dr. Charles Moon, aka moonpod, pers. comm.). Additionally, any medication with significant antibiotic properties will act upon the bacterial populations living in the system, and will foster the development of drug resistant bacteria (Dr. Ron Shimek, pers. comm.).

Treatment Option 14: Garlic

Garlic is another of the alternative treatments for Cryptocaryon to be touted lately. I have read of many people reporting using it "successfully" as a preventative. The difficult part in assessing these reports is whether the fish would have developed Cryptocaryon in the first place. And, when someone claims it to be a "cure," how can they definitively rule out natural, acquired immunity or even confusion over Cryptocaryon's life cycle.

At the very least, garlic does have some proven anti-bacterial, anti-fungal, anti-parasitic, and antiviral properties (Bartelme, 2003 and and Cortes-Jorge, 2001). I included it here because this treatment has shown enough promise to warrant further scientific evaluation. Unfortunately for us, all the real money in this industry is directed to commercial food fish, not our ornamentals. With other effective and inexpensive treatments available, I don't know if grant money will ever be directed into finding out if this alternative treatment conclusively works. Perhaps we could convince the fine marketing people at Mrs. Gordon's that they should try a pre-flavored version of their famous fish sticks by feeding the fish garlic. I can just hear the ad now, "A hint of garlic in every bite."

My biggest problem with the use of garlic is the mythology that has developed regarding it. This all began quite simply and innocently. Kelly Jedlicki was studying the use of garlic as an intestinal dewormer. For those who don't know who Kelly is, she is affectionately referred to as the "Puffer Queen" as they are her favorite fishes and oftentimes are brought into the trade polluted with various worms. As I said, she was examining the effectiveness of garlic against nematodes and cestodes on impacted puffers when she noticed a general decrease in Cryptocaryon irritans incidence. Later on, she proposed feeding garlic to fish as a preventative for Cryptocaryon irritans. From there the legend of garlic has spread. Feeding garlic to fish is now an accepted cure for Marine Ich by some individuals. Furthermore, I have read of people merely hanging cloves of garlic in their tank in an effort to ward off the parasites, like some sort of bad vampire movie. And lastly, I have recently heard of a surprising number of hobbyists who soak their corals' food in garlic in an effort to combat possible pathogens when target feeding them. It goes to show that garlic has become an all-purpose wonder drug in some peoples' eyes based on little more than anecdotal observations.

Treatment Option 15: Ginger

First garlic, now ginger. Is anyone else starting to get hungry? Either I am going to whip up a plate of Roasted Garlic Fettuccini Alfredo or mix up some Wasabi and get busy rolling some Sushi Maki.

Ginger is the newest homeopathic treatment to be suggested. The main thread to this discussion is located here, I waded through the entire thing. It was up to 11 pages and 258 individual posts when I read it. A good portion of the thread is devoted to an ongoing debate about whether this "experiment" was scientific and/or valid. It was neither. The next biggest group of replies debated which side of the previous debate was being rude in their replies. I would say there were some rude people who happened to be on both sides of the argument. Then there was a bunch of people posting nothing, just tagging along so they could get the email notifications. I hate to say it, but the vast majority of the replies were useless as far as determining whether or not ginger was effective at all.

I will attempt to sum up the essence of the thread to save you the time in reading it. Cratylus saw some Ich in his tank. He added ginger to his homemade frozen fish food. The Ich went away. There is no telling whether or not the ginger cured the infection or if natural immunity did. Then, Cratylus specifically purchased a Purple Tang that had a heavy infestation. He brought that fish home, placed it in a separate quarantine tank, fed it the same food, and the Ich went away again. Some people pointed to this experience as being proof. The problem is, moving a fish from an infected tank to a clean tank is a proven cure. It is one of the variations on the daily water change method that I mentioned in my first article on Cryptocaryon irritans (Colorni, 1987). In that paper, Colorni describes moving an infected fish between two tanks. The tanks are cleaned and dried between uses, thereby ridding them of tomonts. He instructs to do this every three days for ten days. This is very similar to what happened with the Purple Tang. There should have been two more moves, but Cratylus got lucky with just the one.

I want to say explicitly that I do not fault Cratylus for attempting something new. There would be no new discoveries without someone trying to push the envelope. I only wish to put his experience in light with what is already known about the biology of Cryptocaryon irritans and known methods or treatments.

Treatment Option 16: Pepper-Based Medications

We have yet another kitchen spice treatment, this time involving pepper. These medications claim to work by stimulating an increased mucus layer response from the fish. This in turn is alleged to be able to slough off the parasites and prevent reinfection. I was able to find only one article on this treatment option. There are several links to "articles" on this product at the Chem Marin website, but only one specifies that it was published in a magazine. Chem Marin's website utilizes frames, so I am unable to give you the exact link to the piece, but the main site is here. Next click on "Reviews" at the bottom of the left side menu. Sandy Cohen's Review #2 from FAMA was the only publication I was able to find on these products. Both Chem Marin and Kent's pepper-based medication are discussed, but without documented, scientific studies, I am leery to recommend these products. There is also no bibliography given for Sandy's article. It would appear that it is just general impressions and background on these products, with no testing or literature referenced. Kent Marine offers a large list of "Considerations for use" about what is safe and what is not here. So if I have not dissuaded you, please review their precautions thoroughly before attempting this treatment.

Treatment Option 17: MelaFix

I have read several threads on various message boards suggesting the use of Aquarium Pharmaceuticals' MelaFix as a treatment for all manors of disease, including Marine Ich. It is important to note, however, that not even the manufacturer recommends this product for any parasite. As such, I certainly cannot recommend it as a treatment for Cryptocaryon irritans.

Treatment Option 18: Mystery Solutions

Lastly, there are a couple of products on the market that do not list their ingredients. Sometimes they say something mysterious about being able to stimulate the immune system of the infected fish. I can only say, I won't use or recommend something unless I know specifically what it is, how it works, and preferably having some type of documentation showing its effectiveness.


Hopefully, you now have a more complete understanding of the disease and the range of some of its treatment options. While I have attempted to cover the entire range of options, there are likely a few that I have missed and there are always new treatments coming onto the market. Regardless of which treatment is most effective, the best medicine is to prevent the outbreak in the first place; an ounce of prevention is worth a pound of cure. Please do invest in a quarantine tank and use it. The cost is minimal compared to buying all new fish and gives you peace of mind in knowing all your additions are healthy. If you do this and keep a good, stable environment in your display tank, you should never need to treat your charges for anything. In the event that you do have a problem, armed with the above options, you should be able to wage a good fight against Cryptocaryon irritans.


I just wanted to take a moment to thank Dr. Charles Moon (aka moonpod), Dr Ron Shimek, Skip Attix, and Adam Cesnales (aka Adam) for their editorial content and ideas. Their suggestions were quite helpful in crafting this two-part series.

If you have any questions about this article, please visit my author forum on Reef Central.


Bartelme, Terry D. 2003. "Parasites and Garlic" Aquarium Fish Magazine, March 2003.

Bassleer, Gerald. 1996. Diseases in Marine Aquarium Fish: Causes, Symptoms, & Treatment Westmeerbeek, Belgium: Bassleer Biofish, page 88.

Bunkley-Williams, Lucy & Ernest H. Williams, Jr. 1994. "Disease caused by Trichodina spheroidesi and Cryptocaryon irritans (Ciliophora) in wild coral reef fishes" Journal of Aquatic Animal Health 6:360-361, 1994.

Calfo, Anthony, pers. comm.

Colorni, Angelo. 1985 "Aspects of the Biology of Cryptocaryon irritans, and Hyposalinity as a Control Measure in Cultured Gilt-Head Sea Bream Sparus aurata" Diseases of Aquatic Organisms, 1:19-22, 1985.

Colorni, Angelo. 1987. "Biology of Cryptocaryon irritans and Strategies for its Control" Aquaculture 67:236-237.

Colorni, Angelo & Peter Burgess. 1997. "Cryptocaryon irritans Brown 1951, the cause of 'white spot disease' in marine fish: an update" Aquarium Sciences and Conservation 1:217-238, 1997.

Fenner, Robert, pers. comm.

Fenner, Robert. 2003. "Cleaning Symbiosis Among Marine Fishes" Tropical Fish Hobbyist, February 2003.

Gratzek, Dr. John B., Dr. Richard E. Wolke, Dr. Emmett B. Shotts Jr., Dr. Donald Dawe, and George C. Blasiola. 1992. Aquariology: Fish Diseases & Water Chemistry. Blacksburg, VA: Tetra Press, page 107.

Grutter, A. S. 1997. "Size-selective predation by the cleaner fish Labroides dimidiatus" Journal of Fish Biology 50:1303-1308, 1997.

Jedlicki, Kelly, pers.comm.

Kollman, Rand. 2003. "Life History and Treatment of Uronema marinum" SeaScope Volume 20 Issue 3, 2003.

Moe, Martin A. Jr. 1989. The Marine Aquarium Reference: Systems and Invertebrates. Plantation, Florida: Green Turtle Publications, pages 288-302.

Moon, Dr. Charles (aka moonpod), pers. comm.

Noga, Edward J. 2000. Fish Disease: Diagnosis and Treatment. Ames, IA: Iowa State University Press, pages 88-95 and 105-107.

Shimek, Dr. Ron, pers. comm.

Wilkie, Donald & Hillel Gordin. 1969. "Outbreak of Cryptocaryoniasis in Marine Aquaria at Scripps Institution of Oceanography" California Fish and Game, 55(3): 227-236. 1969.

Yoshinaga, T. & H.W. Dickerson. 1994. "Laboratory Propagation of Cryptocaryon irritans on a Saltwater-Adapted Poecilia Hybrid, the Black Molly" Journal of Aquatic Animal Health 6:197-201, 1994.

Online Resources:

Further Reading:

Dickerson, Dr. Harry W. 1994. "Treatment of Cryptocaryon irritans in Aquaria" SeaScope, Volume 11, Summer 1994.

Siegel, Terry. 2002. "Cryptocaryon: An Old Enemy" Marine Fish & Reef 2002 Annual.

ReefKeeping Magazine™ Reef Central, LLC. Copyright © 2002

Marine Ich/Cryptocaryon irritans - A Discussion of this Parasite and the Treatment Options Available, Part II -