All members please comment: Barrier Reef ICH Study


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Please comment on this study of wild fish population ich infestations from the Barrier Reef. Some infestations were at 100% levels. I believe this study is in stark contrast to the popular stance that ich is rare in the wild. Please comment on how this knowledge affects your current quarantine philosophy.

DAO 25:159-167(1996) - AbstractInfections of Cryptocaryon irritans on wild fish from southeast Queensland, Australia
Diggles BK, Lester RJG
Wild-caught marine fish from 3 sites in SE Queensland, Australia, were examined over a period of up to 13 mo for infections of the parasitic ciliate Cryptocaryon irritans. Infections of C. irritans were found to be common on the fish sampled. Out of a total of 358 fish (14 species), 239 (66.7%) from 13 species were found to be infected. At Site 1 at the mouth of an estuary, the prevalence of C. irritans infections was 79% and the mean intensity was 12.9 parasites fish-1. At Site 2, a coastal bar area, the prevalence of infection dropped to 66% and a mean intensity of 5.0 parasites fish-1, whilst at Site 3 on the Great Barrier Reef, prevalence was lowest at 51% with a mean intensity of 2.3 parasites fish-1. The study concentrated on 2 sparid fishes, Acanthopagrus australis from Sites 1 and 2 and Gymnocranius audleyi from Site 3. The prevalence of infections on A. australis from Site 1 (n = 101) was 100% with a mean intensity of 14.6 parasites fish-1, whilst at Site 2 (n = 74) the prevalence was 88% at a mean intensity of 5.2 parasites fish-1. There was no apparent seasonality in prevalence or intensity of infections at Sites 1 and 2 despite water temperatures ranging between 15 and 27*C. At Site 3, the prevalence of infections of G. audleyi (n = 39) was 38% with a mean intensity of 1.9 parasites fish-1. The diameter of the tomonts collected from A. australis from Sites 1 and 2 varied inversely with water temperature, and was not related to host size. Our results show that infections of C. irritans are common on wild fish, not rare as previously thought. This may be partially due to the increased sensitivity of our tomont collection technique. Our data suggest that C. irritans may exhibit a degree of host specificity in the wild, and also that its natural distribution can be extended into estuaries and seasonally into warm temperate waters.

Thanks for those of you who responded. I currently carry ich in my reef aquarium. My Regal Tang has occasional bouts. All other inhabitants remain healthy. To the eye that is.........

Your thoughts please.

It doesn't change my approach to the hobby at all.

Those fish are in the wild. My fish are captive in a glass cage. My fish can't swim away from large numbers of the infecting organisms.

A fish that gets Marine Ich now and then in your tank is suffering. I don't like watching my fish suffer from any stress I can remove them from. So, since 1970ish I have not had Marine Ich in my display tanks.

Lastly the percentages quoted in that region doesn't match the percentages I see in my quarantine process. I quarantine fish and less than 35% of them have come to me with Marine Ich. I have not seen any trend up or down with this number, but numbers fluctuate. But then, this is only about 1,700 fish I've seen these last 35 years. :)


Understood, and I am all for the pathogen free display. However, many people I have talked to on the threads have ended up with ich inspite of quarantine efforts. I was wondering if visual inspection was accurate enough to determine whether or not a fish has ich. Many fish do not present. Now Steven Pro has suggested that all fish in confinement will present due to the overwhelming numbers in a small area, stress etc... I have seen with my own eyes fish in the LFS that cease to present once aclimated in good conditions with no cure having been administered. Upon completion of the life-cycle of the parasite the fish still cease to present. Upon transport the fish presents, or doesn't. So my real question is, shouldn't all potential carriers of this parasite be treated regardless of visual signs. To insure a pathogen free display. One parasite slipping by the quarantine procedure due to low levels of parasite numbers. Like in the gill plates. A fish with great immunity to the parasite as evidenced in the wild will not show visual signs. Just like the healthy non-diplaying denizens in my tank who simply do not get it (at least visually) even in the presence of ich. I am opting for quarantine with treatment for certain specimens that are known ich carriers. As per Steven Pro's opinion. I am considering going after all my fish and treating them all. This is what has been suggested by many experienced aquarist on the threads. What I don't understand is why all wild fish aren't treated due to the numbers if fish that are non-displaying carriers that are advocated in this study. The presence of symbiotic relationships, cleaner organisms etc.. All suggest that parasites are fairly common in the ocean. I am just amazed at the two camps. I have a 30 year veteran dealer who has a Tang that shows signs of ich once every couple of years. The rest of his specimens never show signs ever. Are they immune or are they just experiencing low levels of infection?

Thanks for the comments.
Fish have been sampled from other areas at other times for Cryptocaryon irritans and the results vary greatly. In Fuji only one out of 36 fish had it. Scraping and samples were taken to examine under a microscope. That is the only way to know for sure if the fish is a carrier. Part of the problem is the parasite is not always imported on an infected fish. It can come in attached in the tomont stage to inverts, rock, equipment etc. It is also possible to import the free-swimming stage, but that is unusual.

Personally I opt for something in-between only treating fish that are obviously infected and treating all fish regardless of the lack of symptoms. I quarantine all fish in hyposalinity. It may not cure every possible type of external parasite, but it sure does cut down on the incedence of infection with Crypt.

Terry B
I've made other posts in threads and won't repeat them here. But there is a lot to this disease that 'doesn't't meet the eye.'

I can assure you that, people who claim to have put disease-free fish in their tank only to have the tank break out with disease, somehow let the organism in. There is plenty of opportunity for error.

Your note about a tang having reoccurrence of the disease doesn't make sense unless you keep reintroducing the disease. See this link for why:

Two keys to a proper quarantine is the eye of the aquarist and time. I find that a large number of aquarists fail in either one or the other, or both, when they do their QT process. If they manage these two, a lesser number fail in properly maintaining control of cross-contamination. I have done it myself!

Your LFS experience has a lot to be accounted for. Most LFS put copper or another medication (or multiple meds) in their fish tanks. I would not be surprised that you can buy a fish from them that looks like it is Marine Ich (MI) free. I know an LFS that runs copper in his fish tanks (most do) and keeps a QT "in the back" to put fish that present. The fish coming and going never completely rids the LFS tanks of MI. Remember, to the ornamental marine aquarium industry, fish are just a commodity. You don't/can't sell sick fish. If they sell you a fish that looks good but probably has MI, then they get to sell you medication, too, don't they?

One important point here: If the LFS claims his fish are disease-free then why not guarantee them for that? Most don't give you a guarantee, providing 'excuses.' There are (albeit very few) LFSs who do offer a guarantee on their marine fishes, though. Why?

There is much more than what meets the eye. You may want to study the parasite more to understand the subtleties is has. Most of what the aquarist hears is 'averages' and 'generalities.'
Re: Ich

Re: Ich

<a href=showthread.php?s=&postid=6948054#post6948054 target=_blank>Originally posted</a> by ZaneBoyJ
Now Steven Pro has suggested that all fish in confinement will present due to the overwhelming numbers in a small area, stress etc...
Take another look at what I wrote in your PM as well as in the other htread you started with this topic. "But more importantly, a fish carrying this parasite and not showing obvious signs of infestation in the wild is very different from the same fish carrying the parasite into the close confines of captivity. In an aquarium and its limited amount of water, the reproductive strategy of Cryptocaryon irritans makes it overload most fishes and becomes apparent in most all cases in a month." There are no gaurantees in life. That goes for aquariums as well.

Certainly treating all fish with hyposalinity as Terry has mentioned is a sound approach if that is what you decide to do.


I have completed an incredible amount study over the last couple of months on this subject. I respect experience and thats why I am posting. I have found these controversies:

Parisitic levels on wild fish (Please show me the Fiji study mentioned above.)

Latency ( I know a guy who has had a reef tank running for 8 years ) His Regal presents signs of ich occasionally, No other fish in the same tank do... I know this individual well. NO additions or deletions have occured in a two year period. Do the other denizens in his tank have immunity?

Steven Pro, by the way I respect you immensely, I will very likely follow your methods to a tee..... Please forgive me if I have misquoted you in anyway. I am just trying to understand how stringent quarantine procedures that only treat fish that present the ich symptoms visually (or known carriers) can be effective. There is a wealth of information suggesting that low level infections cannot be detected by eye. What started this whole thing with me is the controversy in quarantine procedures from knowledgeable people such as yourself. The controversy outlined here: "Treat all fish for Ich in quarantine regardless of signs" or "Treat only fish with visible signs and known carriers". And of course the other camp, "Don't treat! Provide healthy water conditions, high turnover rates, sub ich sized micron filtration, ozone, UV and most of the ingredients of a very good plate of pasta. :0)

Ps. Sorry I started two threads. I got carried away on the subject. You will notice I have been a lurker since 2003. I just don't post.

I appreciate all the discussion.
No offense intended with my remarks and none felt by me. I just don't want anyone (including yourself) to get the wrong impression.

Treating all fish is a very safe strategy. I just don't chose to treat fish that I feel have very low risk. But, we all have to decide what our own comfort level is regarding that risk.
Stop Parasites

Stop Parasites

While on the subject of Ich. I have ordered a 32 oz bottle of "Stop Parasites". I perused your test with this magic elixir on the captive Xenia. I am thinking of trying to talk my LFS store owner/friend into conducting some trials on this stuff. He has the equipment, freshly transported fish and inverts..... Is this worth the pursuit. I am having a difficult time finding successful users of the product. Bob Fenner reports knowing two credible users of this product, who had success. However, he doesn't support its use. Judging from your responses on the subject, you are skeptical of anything positive regarding pepper based products. Comments?

Latency ( I know a guy who has had a reef tank running for 8 years ) His Regal presents signs of ich occasionally, No other fish in the same tank do... I know this individual well. NO additions or deletions have occured in a two year period. Do the other denizens in his tank have immunity?
Then it wasn't Marine Ich (Cryptocaryon irritans).

I have done studies myself that show that Marine Ich doesn't infect after 10 months.

You might keep in mind that it is impossible to be an expert in every aspect of our hobby. Some people are very knowledgeable about lighting spectrums, others excel in propagation, while still others are adept at DIY projects. You will find that the most knowledgeable people in any aspect of the hobby take a special interest in that area. I think it is safe to say that Steve, Lee, and I take a special interest in fish disease and health management.

Terry B


Wow Lee, I don't know what to tell you. Lonzo has over 30 years in fish keeping. He owns a 10,000 sq. ft. facility LFS. Million dollar store, he couldn't be handing out death and have been so successful, I hope. I honestly believe that he knows what ich is.... I know that flies in the face of what you know. I have read other stories on the boards Wetweb, etc that support these same events. Its these events that have me second guessing my techniques in dealing with it. Everyone has an opinion, very few seem to have controlled clincal evidence to support stories like this. I gotta tell you though, I believe this guy when he tells me he has a tang that gets ich from time to time, while the rest of the fish show no visual signs or strange behavior. (I think his hands are dry by the time he gets home from his LFS). More shocking, this guy doesn't use chemicals for Ich. He sticks with high water turnover, micron filtration, healthy diet.

I now have a hundred hours of ich reading easily. The mysteries stack up like this:

Parasitic numbers in the wild (argued about)
Dormant attributes of Ich (argued about)
Fish immunal response mechanisms (not understood by anyone)
Lack of empirical evidence to support the claims of hobbyist. (The biggy)

Hobbyist like myself are giving anecdotal evidence. Which is fine, however, I believe in hard facts. Clinically controlled studies and results. Saying a fish is ich free based on visual inspection is absurd. Most of the studies I have perused only cover mariculture projects. Like rearing fish in cages for the food industry. Ich levels are determined at the business end of a microscope. I can't stick my head in the sand and ignore what I read. The only way to assess whether a fish has or Ich or not is by this method. IMHO.. So quarantine withouth treatment applied just because a fish shows no symptoms visually is not absolute proof you are not getting ready to place ich in your tank. Treatment itself is not absolute assurance. I will admit, that it is way better than plunking a new arrival straight into the display. Microscopic inspection isn't feasible for the hobbyist in most cases. So I have arrived at a new (old) possible plan for me. I am going to somehow catch my wards (ordered a fish trap last night) and place them in a quarantine tank with a copper treatment. I will go fallow for a long time, because I want to be certain. I am abandoning my friends approach, even though I am in the same situation. A regal with occasional spots, usually taken care of by the cleaner shrimp. All other denizens have a healthy appearance. I will be following Steven Pro's treatment methodologies. I think he is type "A" enough to have proven his strategies in a thorough manner. I will match his medicine cabinet and equipment to a "t". I ordered everything last night, right down to the sponge filters.

I appreciate all of the conversation and replies. Its all very helpful. Mr. Pro thanks for your efforts at educating the hobbyist. I have witnessed to much death and destruction while perusing the boards. Its almost to much to handle for a seasoned diver. The Crown of Thorns on one side and uneducated well meaning hobbyist (such as myself) on the other side. Will the creatures we love survive it all?

Ich out!
Ich Vaccine

Ich Vaccine

Fishing for a Cure

Two marine biologists at the University of Hawaii are developing a fish vaccine to prevent a widespread and often fatal parasitic problem

Jo-Ann Leong and Teresa Lewis want to make sure Hawaii doesn't get the tropical "ich." Though the letter "t" is missing, the meaning is the same - except ich is an itch that fish get from parasites.

Leong and Lewis, who are marine biology researchers at the Hawaii Institute of Marine Biology (HIMB) on Coconut Island in Kaneohe Bay, have initiated a program funded by the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration and the federally funded Hawaii SeaGrant program to study this warm-water scourge. Leong's fish virology research has brought in about $850,000 over the past few years.

The cryptocaryon parasite burrows into the mucous membranes of warm-water fish and irritates their skin. The parasite causes white lesions. Itchy fish rub themselves on rough or hard surfaces to try to alleviate the irritation and often rip off chunks of their skin.
In many victims the parasite leads to other health problems and eventually to death. "They itch, get real sick and many of them die," says Leong, who is the director of the HIMB, a unit of the University of Hawaii's School of Ocean, Earth Science and Technology (SOEST).

Just as they do in the rest of the tropics, cryptocaryon infect many Hawaii fish varieties, including opakapaka, kahala and various snappers and reef fish. That's a big problem as the state seeks to grow its aquaculture industry. In 2002, according to the USDA, Hawaii aquaculture products had a gross value of $25 million. Fish are one of the fastest growing aquacultural products.

THIS WON'T HURT A BIT: Jo-Ann Leong and Teresa Lewis of the Hawaii Insitute of Marine Biology (HIMB) want to immunize Hawaii fish. Photo: Ronen Zilberman

Since 1998, the value of finfish grown in Hawaii has increased 180 percent, from $958,000 to $2.638 million. The Hawaii state Department of Agriculture hopes to grow that segment to $5 million by the latter half of this decade. With the success of the moi farms off the Waianae Coast and promising developments in other finfish aquaculture operations on the Kona Coast and at the Oceanic Institute near Makapuu, that goal appears increasingly realistic.

To meet it, though, the fish farmers may need Leong and Lewis to help them fight fish diseases that spread like wildfire among confined populations typical in aquaculture operations. Both Leong and Lewis are world-class experts in fish diseases, with broad experience in how the immune systems of fish function. Their plan? First they want to sequence the genome of cryptocaryon and get a clearer picture of how the parasite infects and affects fish. Then they hope to develop a fish vaccine that aquaculturists could easily administer to their fish either through simple injections or skin-absorption techniques.

Such vaccines might sound exotic, but are actually fairly commonplace. Leong developed two fish vaccines while working at Oregon State University in the 1970s and 1980s, which were among the first in the field. Those vaccines immunized salmon and rainbow trout against two different types of fatal viruses that had plagued the fish-rich rivers of that rainy state, as well as its fish farms. Those farms represent businesses worth hundreds of millions of dollars in the Pacific Northwest. One of Leong's vaccines, which guards against a virus that damages fish livers, is widely used by fish farmers in Norway.

Today, companies manufacture 10 different vaccines protecting dozens of farmed species. Many fish farms have been able to dramatically cut their use of antibiotics by immunizing their fish.

However, Leong and Lewis face some obstacles. Decoding the genome of a single-celled parasite is actually far more complicated than decoding the genome of a virus. "A virus genome only carries 12 kilobytes of information. A parasite genome will carry megabytes of information," explains Leong, who expects the effort to take more than a year.

Further, while the white spots and subsequent health problems in fish caused by cryptocaryon are well documented, scientists understand very little about the life cycle and habits of cryptocaryon. This information, says Leong, will be necessary in building a vaccine.

However, Leong and Lewis hope to copy the basic vaccine-building methodology that Leong used in the two salmon-virus vaccines. This will entail isolating the cryptocaryon gene that encodes a surface protein of the parasite and then, placing that gene into a DNA vector that would be easily absorbed by or injected into fish. By doing so they actually program a strong defensive response to the parasite into the fish's immune-response system.

To ensure that the added gene does not disrupt the fish's own genome, Leong and Lewis can build a self-destruct function into the vaccine, which ensures that the injected genes do not persist. "It's only one gene, so it's very safe. And it's extremely effective," says Leong.

A cryptocaryon vaccine could also prove lucrative. Leong and Lewis hope to patent the technology so the UH will have the option of licensing the vaccine to a commercial entity for widespread production and use around the world. What's more, these types of fish vaccines could become increasingly important in maintaining aquatic populations. Says Leong, "There are disease outbreaks in wild fish quite frequently.

Our fisheries are beginning to decrease. So we are going to have to practice conservation biology to bring some of these fish back to healthy levels. And we are going to have to understand how to rear them without disease."
Here is a comment that I wrote in part five of a series of articles that I wrote a couple of years ago on the subject of Cryptocaryon irritans:

"The ability of fish to develop some level of immunity to Cryptocaryon irritans suggests that an immunological approach such as vaccination may be feasible. However, such a vaccination has yet to be developed."

Of course we would all like to see a successful vaccine against Cryptocaryon irritans. While such a vaccine would be beneficial to commercial aquaculture, it is questionable if this will have practical application for hobbyists keeping marine aquaria.

Terry B
Fish vaccines aren't new of course. The problem has been and is how the vaccine is delivered. Inoculations of each fish would be tedious. Ingesting a vaccine or one that could be added to the water for absorption would be the ideal.

Although research has always shown on a mini scale there are many ways; it's the macro scale that poses the greatest challenge.

This kind of 'announcement' I find disturbing when, there is a skewed version of what we know about Cryptocaryon irritans. That is, the microbe is presented as a terrible unknown that these guys will study and defeat. It really isn't all that unknown. It makes for 'smart journalism' to make it sound mysterious, I suppose.


I don't know Lee, I have read multiple studies that suggest the mechanisms that drive the immune response of the unfortunate hosts as being an "unknown". It could be these natural defense mechanisms that are the basis for a successful vaccine. With more commercial industries opening up that farm raise food fish, money to drive research will come available. The hobbyist may just reap the benefits by proxy. It just doesn't seem that knowledge of the pathological characteristics of this parasite is as complete as you suggest. At least not from my findings thus far...IMHO of course. :0) I defer to your expertise if it is otherwise..

About the only thing I can think of that is unclear regarding Cryptocaryon irritans is whether or not it engages in sexual reproduction as well as the commonly described asexual method.
here is one for you all.I had 2 tanks running both for 2 years.Both were to the naked eye disease free with all fish and corals healthy.I had to take down one of the tanks and put one fish from tank a into tank b.One month later I had a major outbreak in tank B.So what was it?

1-was the fish from tank a infected

2-did the intro of a new fish cause stress and trigger the outbreak that was already there

3-were fish in tank a and tank b immune to disease in there indivudial tank and when introduced caused an out break

4-it can go on and on

So now when I take a fish from one system to another I quarentine that fish even if that fish has been healthy FOR YEARS!!!!My OPINION based on my own OBSERVATIONS is that despite quarintine most fish are infected and adverse conditions will cause an outbreak even in fish that were quarentined/treated and or around for years.Despite what I have said I do quarentine all new fish because since I have done this my losses are much lower than before