Ich infection rate in the wild

[Humblefish]

I read all the time people saying how infection rate in the ocean is low because the fish are healthy and have strong immune systems. Well, this study mirrors what I've read from other parts of the world (e.g. Great Barrier Reef): The Prevalence of Cryptocaryon irritans in wild marine ornamental fish from Vietnam

Abstract. Wild-caught ornamental marine fish from NhaTrang (Khanh Hoa) and Ha Long (Quang Ninh) in Vietnam were examined over the three sampling batches corresponding to the spring, summer and autumn times for the prevalence of Cryptocaryon irritans. Out of a total of 211 fish (15 species), 143 (67.7 %) were found to be infected with the mean intensity of 7.67 parasites per field of view (x4 magnification). The prevalence of C.irritans in fish caught during the spring (91.0 3% on average) was significantly higher than that of the fish caught during the summer (39.29 %). A wide variation in the prevalence of the parasite was shown among the fish species. The highest prevalence and intensity of the infection occurred in Plataxteira, Diodon holocanthus, Paracanthurus hepatusat 100 % of infection and density of 12 parasites/field of view (x4 magnification) while and the lowest prevalence of C. irritans appeared on Rhinecanthus aculeatus, Zancluscornutus, and Zebrasoma veliferum with less than 50% of fish infected. Clinical signs of fish infected of C.irritans showed such as tiny white spots on skin, gills, and fins; ragged fins, changes in skin colour, cloudy eyes and increase mucus production.

Conclusion
It is clear that Cryptocaryon irritans is common all year round in ornamental marine fish sampled in Vietnam. However, the prevalence and intensity of the infection vary widely with the fish host and captured seasons. Some species are very susceptible to the parasite infection (up to 100 % infected) while others are infected at a much lower rate (less than 50 % infected). A seasonal variation in the prevalence and intensity of C. irritans infectionwas also clearly presented. The highest prevalence of infection occurred during the spring and the lower values were shown in the summer. These findings provide important information which can be employed by aquarists in keeping and treating this parasitefor ornamental fish in a confined condition.

So why aren't fish in the ocean dying left and right from Ich? DILUTION. And the only way to replicate this in an aquarium environment is to (A) Keep the parasites out of your tank in the first place through proper quarantine and/or (B) Use a tool to keep parasite populations in check. These include a UV sterilizer, diatom filter, ozone, etc.

The study lists out which fish are more naturally resistant. These include Triggerfish, Moorish Idols (surprisingly) and Zebrasoma Tangs. Whereas Batfish, Puffers and Hippo Tangs were far more susceptible. (There are many other species listed below.)

The study also touches upon Ich and temperature:

Fish caught in the spring infected by C.irritans are at the highest prevalence of 91.03% on average with various fish species infected at 100% of prevalence such as C. adiergastos, P. hepatus, A. frenatus, P. volitans. The lower prevalence of C. irritans infections was observed in the fish captured during the autumn (64.94 %), while the lowest value occurred on the fish captured during the summer (39.29 %). According to Yoshinaga [14], who conducted a study on the impacts of temperature and dissolved oxygen levels on the development of C. irritans, temperatures for the optimal growth of most strains of Crypto caryon are between 23 and 30 °C [10, 14]. The development of the parasite was significantly damaged at the temperature above 31 C and no parasite was recovered from any fish reared at 34 C. These could be the reasons related to the variation of the higher prevalence of parasite infections on fish captured in the spring compared to the summer.

^^ The above suggests keeping an aquarium at or below 22C/72F is one possible strategy for managing Ich. (Probably only suitable for a FOWLR.) And for going fallow, raising the temperature to 31C/88F should help "damage" any tomonts leftover in the tank. Again, this strategy is probably only suitable for a FOWLR as corals/inverts most likely cannot survive that high of a temp. And going any higher risks killing all the nitrifying bacteria in the tank.

In addition, the study suggests that maybe buying fish only in the summer = less diseased fish. :unsure: Just keep in mind this means summertime where the fish was collected. (For example, summer typically lasts from May to October in Vietnam.) And of course, being able to buy direct from collectors (transshipping) helps because the fish then doesn't have to pass through the disease-ridden wholesale facilities.

 

[Wolf89]

Great info. Do you have any links that I can read up on diatom filters?

 

[ca1ore]

Nice to see some actual research. Has always seemed somewhat self evident to me and makes perfect sense if you think about the reproductive mechanisms of ich. Thousands of theronts are produced because the vast majority of them never encounter an acceptable host. The confined space in our tanks short circuits the natural culling process so our captive fish are attacked by order of magnitude higher numbers of theronts. I’ve always thought of things like UV and DE filters not as a cure but as a way to reduce parasite ‘pressure’ to more manageable levels.

Thus, I run a large UV on my system at level 2 sterilization levels. Doesn’t eradicate ich but keeps it under control. I did purchase a large DE filter, but never got around to hooking it up. Maybe someday.

 

[Humblefish]

Great info. Do you have any links that I can read up on diatom filters?

Diatom filter for treating external parasites?

In another thread, it has been postulated that a diatom filter can be effectively used to filter out the free swimming stage of ich, velvet, etc. The poster provided the two links below as evidence to support his theory: http://aquarticles.com/articles/management/Lawler_Diatomfilters.html...

www.reef2reef.com

 

[Wolf89]

Diatom filter for treating external parasites?

In another thread, it has been postulated that a diatom filter can be effectively used to filter out the free swimming stage of ich, velvet, etc. The poster provided the two links below as evidence to support his theory: http://aquarticles.com/articles/management/Lawler_Diatomfilters.html...

www.reef2reef.com

Would one of those magnum polishing filters with diatomaceous earth work similarly?

 

[Humblefish]

Would one of those magnum polishing filters with diatomaceous earth work similarly?

I know people who have used 1 or 2 during a velvet outbreak, and it does seem to help. The operative word here is help; it doesn't eliminate the problem. For larger aquariums you'd have to plumb a pool grade DE into the system:



I've always wanted to experiment with doing that, but just haven't had the time.

 

[Reef AquaCult]

Pretty surprising 75% of hippo tangs sampled had ich. I would have expected the number to be MUCH lower. Its also pretty impressive to think of the with amount of water passing over the reefs the free swimming parasites can even encounter a fish to feast on. Thanks for the info!

I wonder if there is any roll to run a copper-based QT protocol at elevated temps to speed the ich life cycle and thereby decreasing the QT duration....?

 

[AZMSGT]

I know people who have used 1 or 2 during a velvet outbreak, and it does seem to help. The operative word here is help; it doesn't eliminate the problem. For larger aquariums you'd have to plumb a pool grade DE into the system:



I've always wanted to experiment with doing that, but just haven't had the time.

Looks much more cost effective and would work on your smaller tanks perhaps?

Diatom Filters

Vortex Diatom Filter Sale. The lowest pricing on the internet. Get the best daels here on diatom filters and aquarium filters.

www.diatomfilters.com

I'm wondering if this is an item that you could build as a hang unit to experiment with

 

[mfinn]

​

The study also touches upon Ich and temperature:


^^ The above suggests keeping an aquarium at or below 22C/72F is one possible strategy for managing Ich. (Probably only suitable for a FOWLR.) And for going fallow, raising the temperature to 31C/88F should help "damage" any tomonts leftover in the tank. Again, this strategy is probably only suitable for a FOWLR as corals/inverts most likely cannot survive that high of a temp. And going any higher risks killing all the nitrifying bacteria in the tank.

So bumping up the tank temp actually does help?
But it's got to be minimum 88 or maximum?
Is there a acceptable range where this helps?

 

[Humblefish]

Looks much more cost effective and would work on your smaller tanks perhaps?

Diatom Filters

Vortex Diatom Filter Sale. The lowest pricing on the internet. Get the best daels here on diatom filters and aquarium filters.

www.diatomfilters.com

I'm wondering if this is an item that you could build as a hang unit to experiment with

Avoid anything Vortex as the motor is prone to overheating and various other issues.

So bumping up the tank temp actually does help?
But it's got to be minimum 88 or maximum?
Is there a acceptable range where this helps?

The study states, "The development of the parasite was significantly damaged at the temperature above 31C (87.8F) and no parasite was recovered from any fish reared at 34C (93.2F)." It also stated that the infection rate was lowest (39.29 %) during the summer months. So apparently Ich doesn't like high temps. The "sweet spot" for Crypto propagation is between 23-30C (73.4 - 86F). Temperatures outside of that are not optimal for growth of most strains of Crypto.

 

[Paul B]

So why aren't fish in the ocean dying left and right from Ich? DILUTION.

Immunity. And they stay immune because they are constantly exposed. Now isn't that special. What a concept.

 

[Humblefish]

Immunity. And they stay immune because they are constantly exposed. Now isn't that special. What a concept.

Apparently immunity is overstated if the infection rate is over 91% during the springtime. A balance of immunity & dilution is the more logical conclusion. And many fish in the ocean just succumb and die to pathogens, pollution, etc. Red tide kills thousands of fish in just Florida every year. Luckily these fish are also prolific breeders (in the wild.)

 

[robbyg]

I am going to buck the data and say I would like to see another study.
I have caught dozens of fish during Scuba diving trips and dropped them straight into my Tank. I have NEVER had a case where the fish in the tank or the newly introduced fish developed Ick. Yeah I am just one person but that article just seems strange to me. I have never seen a fish in the ocean with Ick. I also have to wonder what are the odds of one of these free floating eggs meeting up with a fish versus getting consumed by the blanket of coral below it?

 

[Humblefish]

I am going to buck the data and say I would like to see another study.
I have caught dozens of fish during Scuba diving trips and dropped them straight into my Tank. I have NEVER had a case where the fish in the tank or the newly introduced fish developed Ick. Yeah I am just one person but that article just seems strange to me. I have never seen a fish in the ocean with Ick. I also have to wonder what are the odds of one of these free floating eggs meeting up with a fish versus getting consumed by the blanket of coral below it?

Infections 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.

Full study: https://www.int-res.com/articles/dao/25/d025p159.pdf

What area do you collect from and which species?

 

[Paul B]

Those infected fish seem to lose those parasites as soon as they hit my tank.

I have also been collecting fish all my life, and I'm old, and throwing them in my tank. Baby flounders, sea robins, baby stripped bass, needlefish, pipefish, seahorses etc and I have never had any disease but I have only been doing them for 50 or so years so maybe in 51 years you have a problem. ;Bucktooth

 

[robbyg]

Infections 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.

Full study: https://www.int-res.com/articles/dao/25/d025p159.pdf

What area do you collect from and which species?

Mostly Caribbean fish and I have been doing it for around 35 years.

 

[Humblefish]

Those infected fish seem to lose those parasites as soon as they hit my tank.

I have also been collecting fish all my life, and I'm old, and throwing them in my tank. Baby flounders, sea robins, baby stripped bass, needlefish, pipefish, seahorses etc and I have never had any disease but I have only been doing them for 50 or so years so maybe in 51 years you have a problem. ;Bucktooth

Dump & Hope works for you and others, but it proves to be disastrous for the vast majority who try it. Especially new hobbyists who lack your experience. I've noticed those who say "I don't QT" and "I've been doing this 20-30 years" usually goes hand in hand. That's great! Start a thread or write a book outlining everything you do which you feel contributes to your success. Let's see if its repeatable. I've read your book twice now, and I still can't figure out everything you've got going on with your tank. Reverse flow UG filter, mud from the beach, clams, food soaking fish oil, feeding live blackworms/whiteworms, running ozone (although you've stopped doing that now). Maybe the parasites get trapped under your filter plate or there's a strain of bacteria (or other microorganism) in your tank which preys upon tomonts or as you like to suggest, your fish are just super immune to everything?? The point is unless your methods are repeatable, they only work for you.

I didn't QT for roughly my first 30 years in this hobby. I can't say I had amazing success, but I had angels & tangs that lived 10-15 years. I would see Ich spots from time to time, but it was mostly manageable. Around 10 years ago I came back from Europe, started up another tank and went back to my old ways. It was a ******* disaster! I was encountering diseases I had never even seen before. Something had definitely changed with the quality of fish being imported into America. Fortunately I had a background in quarantining fish from my days working for an aquarium maintenance co. It's a PITA sometimes, and not every fish makes it thru QT, but the ones that do are with me (or whoever I give them to) for a very long time. But yes, there is a learning curve to successful QT. It's not "everything's perfect, my fish never die" like when you don't QT. I will say whenever I visit a friend who does not QT, it's absolutely amazing to me how many of their fish I saw during my previous visit either jumped out or mysteriously disappeared... But they never die from disease!

 

[Paul B]

I've read your book twice now, and I still can't figure out everything you've got going on with your tank. Reverse flow UG filter, mud from the beach, clams, food soaking fish oil, feeding live blackworms/whiteworms, running ozone (although you've stopped doing that now).

You may have to read it three times to get the full effect.

I agree with you Old Buddy, both systems work and there are also problems with both of them. It is what it is and whatever works for you is what you should do.

I do have issues with people who said they used my system and lost all of their fish' then I find out they fed flake food, "observed" fish for a period of time in a separate tank, dipped, medicated or did something or didn't do something that I suggested.

It's the same with quarantining, if you don't follow it word for word, you can have problems.

The two systems can't be mixed, pick one or the other and go with that. You will have success with either system if you follow it as it is supposed to be followed.

I designed my method over 40+ years with many failures as it doesn't happen over night. It is similar with quarantining, there are things that must be done correctly and that is where people start to have trouble with both systems.

By the way, after this Corona Virus thing, when are you coming to NY?

My wife is from Corona (Queens) and we go there to drink Corona Beer.

But we are safe so far as it is sparsely populated out here and everything is closed anyway.

Right near here, maybe 8 miles away is the largest Corona infection in NY, Southold. So we don't go there.

We were supposed to go there for an Oysterfest, but of course that is cancelled.

 

[WvAquatics]

@Humblefish @Paul B Have to say love watching you two go back and forth with qt or not. It's very informative and hopefully helps new people to reefs like me understand different ways to do things. Both areas seem to be alot of work. Keep up the debate we are learning

 

[Halal Hotdog]

Dump & Hope works for you and others, but it proves to be disastrous for the vast majority who try it. Especially new hobbyists who lack your experience. I've noticed those who say "I don't QT" and "I've been doing this 20-30 years" usually goes hand in hand. That's great! Start a thread or write a book outlining everything you do which you feel contributes to your success. Let's see if its repeatable. I've read your book twice now, and I still can't figure out everything you've got going on with your tank. Reverse flow UG filter, mud from the beach, clams, food soaking fish oil, feeding live blackworms/whiteworms, running ozone (although you've stopped doing that now). Maybe the parasites get trapped under your filter plate or there's a strain of bacteria (or other microorganism) in your tank which preys upon tomonts or as you like to suggest, your fish are just super immune to everything?? The point is unless your methods are repeatable, they only work for you.

I didn't QT for roughly my first 30 years in this hobby. I can't say I had amazing success, but I had angels & tangs that lived 10-15 years. I would see Ich spots from time to time, but it was mostly manageable. Around 10 years ago I came back from Europe, started up another tank and went back to my old ways. It was a ******* disaster! I was encountering diseases I had never even seen before. Something had definitely changed with the quality of fish being imported into America. Fortunately I had a background in quarantining fish from my days working for an aquarium maintenance co. It's a PITA sometimes, and not every fish makes it thru QT, but the ones that do are with me (or whoever I give them to) for a very long time. But yes, there is a learning curve to successful QT. It's not "everything's perfect, my fish never die" like when you don't QT. I will say whenever I visit a friend who does not QT, it's absolutely amazing to me how many of their fish I saw during my previous visit either jumped out or mysteriously disappeared... But they never die from disease!

This hits the nail no hard on the head. We all HATE quarantining fish, but it is the only way I have been able to get replicable results. The problem I have is individuals that state you can replicate my none QT results if you follow exactly what I did...... I cannot get mud from your backyard, and the mud from my backyard doesn't help with external parasites. I have tried most of the methods out there over the years and like Humblefish states, whenever a new tank goes up the deaths begin. We are all striving for the best way to keep healthy fish. One very positive change is there are vendors starting to QT fish prior to sale. You end up paying a premium, but for those that do not have the ability or want, they can purchase a healthy fish and drop him straight in. Of course no method is 100% successful so observing the fish before adding to your DT would still be recommended.