Marine Ich - Myths and Facts

Reef Aquarium & Tank Building Forum

Help Support Reef Aquarium & Tank Building Forum:

Status
Not open for further replies.

leebca

Well-known member
Joined
May 22, 2006
Messages
2,243
Location
So CA
Marine Ich (Cryptocaryon irritans)

One of the marine aquarist’s devils. :evil: So many articles have been written about it. Many are long or are in multiple parts. A lot is known about this marine fish disease because of the many $$$ put into research by the fish farming and aquaculture industries. First discovered (or the better word is 'noticed') in the 1800's and later more understood in the 1900's, we’ve learned about all there is to know about this parasite by the 2000's.

I don’t want to write a long post on Marine Ich (MI) but the reader, in as brief of space as possible, should know some truths. The aquarist 'sees something' and then 'guesses' as to what it means and thus starts another round of rumors. It's almost a type of voodoo. It's easier to listen to a rumor of a short absolute statement then it is to read and understand the results of decades of studies and experiments. It is easier to try and take shortcuts with this disease by believing the parasite to be able or capable to do things or die from things it just can't, then it is to do the work to kill it, control it, or prevent it by the means that are known to work.

It's time to separate out the rumors from the facts and the subjective observations (which start rumors) from actual scientific studies. In bullet form, here’s what is known:



Life and Visuals:

1, The parasite has several ‘stages’ in its life cycle. Cyst in aquarium (usually on substrate, decoration, wall, equipment, or rock) ruptures into free-swimming parasites that burrow into fish, grow into a visible white nodule that is ‘pregnant’ with more parasites, that usually falls off the fish to form a cyst that releases more free-swimming parasites and starts the cycle over again.

2. Only time a human can see this parasite with the naked eye is when it is ‘pregnant’ on the fish and has formed a white nodule. (The white spot is about the size of a grain of table salt or sugar). [NOT ALL WHITE SPOTS MEAN MARINE ICH].

3. Parasites that have just burrowed into the fish are not visible until 2.

4. Cycle can be completed in less than 7 days, but usually within 24 days BUT can go as long as 72 days. Literature usually quotes ‘average’ number of days. 72 days is rare; 60 days usually encompasses more than 99.9% of the observations and research.

5. This is not the same as the freshwater disease, Ich (Ichthyophthirius multifilis) but it was named after it?! :mad: This leads freshwater aquarists to thinking the wrong things about Marine Ich, adding to the myths and rumors.

6. MI is not very sensitive to temperature changes. That is, increasing the temperature does not significantly decrease the life cycle time. This is not true with Freshwater Ich (which is where this rumor of raising the temperature on a marine aquarium with MI comes from).

7. MI can live and reproduce in temperatures as low as 50F and as high as 90F. Thus temperatures that would kill MI would first kill or severely stress most tropical marine fishes.

8. Spots appear then disappear as MI goes through its cycle. Remember 2. This 'disappearing act' is what leads uninformed aquarists to believe the fish are cured. This is the dumbest thing aquarists can possibly think about this parasite! :(

9. Parasites seem to come in two types: one that only infects gills and one that infects gills and the fish’s body. The tissue of the gills has more exposure to the parasites because a lot of water goes by the gills as the fish ‘breathes’ or ‘swallows.’ Thus, there is an increase in chance the free-swimming parasite will get to the gill. This is one reason why fast breathing (over 90 swallows in one minute) is one of the symptoms of possible infection.

10. The parasite burrows into the fish, below the mucous layer and into the skin or gill itself. (This is why cleaner fish/shrimp can’t get to it in order to remove them from the fish). The second dumbest thing an aquarist can think: I'll get some cleaner fish or cleaner shrimp to remove/eat the parasite. THESE MARINES DO NOT EAT THE MI PARASITE NOR WILL FISH OR SHRIMP REMOVE THE PARASITE FROM THE INFECTED FISHES. Research has shown that the intestinal tracks of cleaner fish and shrimp do not contain MI parasites - - these lifeforms don’t eat MI off of infected fishes.

11. Parasite is transmitted in water (free-swimming and cyst stages), or by falling off of an infected fish (even one that seems healthy because of 9.). This means that water OR fish from another aquarium can carry the disease to another aquarium.

12. The parasite can infect bony fishes, including eels, sharks, and rays, though many species of fish, like Mandarins, have a good resistance to MI, they can still be infected and can harbor or carry the parasite. Invertebrates, snails, crabs, corals, plants, etc. are not affected/infected by MI, but the MI can be in their water, shells, etc.

13. There is no such thing as a dormant stage for MI. The parasite can’t wait around for another host. It MUST go through its cycle. Dr. Burgess recorded that in the cyst stage, he found the longest existing cyst to last for 60 days before releasing the free-swimming parasites. This is rare but possible. This led to the recommendation by many to allow 8 weeks for a fishless tank to be rid of this parasite.

14. INTERESTING FIND: If no new MI is introduce into an infected aquarium, the MI already there continues to cycle through multiple generations until about 10 to 11 months when the MI has ‘worn itself out’ and becomes less infective. A tank can be free of an MI infestation if it is never exposed to new MI parasites for over 11 months.



Treatments:

1. Hyposalinity - Using a refractometer, hold salinity at 11ppt to 12ppt until 4 weeks after the last spot was seen. (Best to use salinity, but if you use specific gravity, that equates to roughly 1.008 to 1.009 sp. gr. units). Raise salinity slowly and observe fish for 4 more weeks. Hard to control pH and water quality during treatment. This is the least stressful treatment for the fish. See: A Fish Hyposalinity Treatment

2. Copper treatment - Follow medication recommendations. Can be effective in 2 to 4 weeks of treatment. After treatment, remove all copper and observe fish for 4 more weeks. Copper is a poison to the fish and creates some stress. The fish may stop eating. See end of this post for other things that can go wrong. See: Copper Medications - Good, Bad, and Ugly.

3.. Transfer method - Fish is moved from tank to tank to separate the fish from the cysts that fall off and the free-swimming stages of the parasite. Two hospital tanks are needed to perform this treatment. The fish is stressed by having to keep moving it between these hospital tanks.

4. Only the above 3 known cures fall into this category: Don't require prescriptions; use chemicals that are not carcinogens to humans; and work 100% of the time when diligently peroformed. Other chemicals will kill the MI parasite, but only in special conditions (not good for the fish) or in lab experiments (not using marine fish). Some chemicals will only kill some of the organisms, letting the others escape death to go on to multiply and infect.

5. Not any of the treatments can be done in a display tank with true live rock. Must be done in a hospital tank or quarantine tank. The hyposalinity and the copper treatment would kill invertebrates, live rock, and other non-fish marine life. Substrates and carbonates interfere with a copper treatment.

6. No known ‘reef-safe’ remedies work consistently. Many aquarists think a particular remedy works when in fact the fish acquire an immunity or defense against the parasite. It’s easy for any manufacturer to have an independent study done on the effectiveness of the ‘reef-safe’ remedy but they don’t because. . .

7. Cleaner shrimp and cleaner wrasses are not known to pick these parasites off of fish. (See 10. above).

8. Freshwater dips can kill some of the parasites on/in the fish, but not all of them because many of the parasites are protected by the fish's skin and mucous layer. (See 10. above).

9. No dip can get rid of these parasites because primarily of 10. above.

10. Let aquarium go fishless (without any foreign saltwater additions (e.g., water from LFS system, water from another tank or system -- use only distilled or RO/DI for evaporation and freshly made, uncontaminated salt water for water changes), without contamination from infected tanks, live rock additions, etc.) for at least 8 weeks and the tank will be free of MI. This 'fallow period' has over a 99.9% chance of success.

11. NEVER combine a copper treatment with a hyposalinity treatment. pH is hard to control in a hyposaline solution. If the pH drops, the copper complexed with water carbonates becomes 'free' and raises the copper content the fish is exposed to. The effect is similar to to overdosing with copper. Not worth the risk. Since they both cure Marine Ich, use one or the other and don't put so much stress on the fish (and yourself).



Defense and Immunity:

1. The fish’s mucous coating can provide some protection from the parasite. The mucous coating is where some fish immunity develops.

2. When water temperature drops, mucous coating is often reduced or lost in marine fishes, that is why sometimes MI becomes visible on the body of the fish after a sudden drop in temperature. This meant, however, that the disease was present and living in the aquarium, infecting fish without the aquarist having been aware of it.

3. No fish, no matter how good its defense is, can stop being infected. A healthy fish will and can be equally infected as a sick or stressed fish. What happens is the aquarists sees one or more fish with the disease and assumes because none are seen on the other fish in the aquarium that they are 'disease free.' NOT. Aquarists can't always see the parasites. See above top, 2., 3., and 9. All fish in an infected tank require treatment. MI is not and opportunistic pathogen - - It can and does infect healthy, unstressed fishes.

4. A weak, stressed, or sick fish will die sooner than a healthy fish, but is no more likely to get infected than the healthy fish.

5. A fish that survives an attack may develop proteins (also in the mucous coating) that will help fend off the parasite (this is a type of immune response). An immune fish will not get infected. Unfortunately. . .(see 6. below). . .

6. An immune fish doesn’t remain immune. Separated from the disease for months, the once immune fish can become MI infected.

7. Immunization seems to work, but not affordable or likely available to the hobby for many more decades. The immunization materials are hard to make, expensive, and slow to produce. Unfortunately, like it states in 6. above, the immunity is short-lived.



Subjective and Non-Subjective Observations, Claims, and Common Myths

1. Tangs seem more susceptible. True. Their mucous coatings are reduced in thickness and composition. They swim up to 25 miles a day in the ocean in search for food so maybe Mother Nature provided them with this as a means of 'escaping' being reinfected by the free-swimming parasites.

2. It goes away on its own. Untrue. Only visible at one stage IF it is on the body or fin of the fish. It’s the life cycle. If it was once seen, then it hasn't gone away -- it's just not visible to the aquarist.

3. It goes away with a ‘reef-safe’ remedy. Untrue. This is one of the biggest and most 'dangerous' of the misrepresentations in the hobby. The aquarist thinks everything is okay when it isn't. What usually has happened is that the parasite has killed the fish it will kill and the rest have developed a resistance or immunity. OR the strain of MI turns to infecting the gills only where the only stage of it can’t be seen by the hobbyist. The parasite is still in the aquarium.

4. It was gone then when a new fish is added, it is there again. Not true. See 3. It wasn’t gone or the new fish brought in the disease with it. A new addition to an aquarium can be the stress which triggers the other fish to reduce their defense or immunity, thus allow the parasite to 'bloom' to the point where the infection is now visible to the aquarist.

5. The fish lived the last outbreak then died during the second or subsequent outbreak. Can be true. The fish had a resistance or immunity that it lost.

6. It was diagnosed as MI spots, then never showed up again. It wasn’t MI or the fish quickly developed an immediate immunity or resistance, or the fish is still infected in the gills.

7. MI can ‘hang around’ almost unnoticed with just a body spot now and then because it often resides just in the gills. True. So ‘it is gone’ after ‘it was here’ is very unlikely.

8. Aquariums always have MI. Untrue. MI can be kept out of an aquarium. Just quarantine all fish and don’t let non-quarantined livestock get into the aquarium. After keeping thousands of marine fishes, my home aquariums have been free of MI since 1970.

9. Fish always have MI. Untrue. In the wild they often show up to 30% infected (or more) but the wild fish survive minor infections. In the tank the parasite can 'bloom.' In the tank the fish can't get away. The combination of bloom and no escape will overcome the fish. In capture and transportation the fish can share the disease and thus many wild caught marine aquarium fishes do have this parasite, but not all.

10. Like 9. a fish can't be made to be totally rid of MI. Untrue. All marine fish can be cured and rid of any MI infection.

11. Just feed the fish well and/or feed it garlic and it will be okay. Untrue. I compare this approach to this one: "Granny has pneumonia. Let's keep her home rather than take her to the hospital. We'll feed her well with chicken soup and vitamins -- and lots of garlic." :looney: Nutrition, foods, garlic, vitamins don't cure an infected fish. An infected fish is sick and is being tortured by the itching and discomfort. Don't let this happen to the fish. Cure it!! :thumbs:

12. A new cure has been discovered. Unlikely. If the aquarist thinks they have found a new cure, then have it researched and independently tested. It's easy and cheap. If it is as good as the above 3 then the professional veterinarians, private and public aquariums, fish farms, and I will use it. The aquarist needs to keep the perspective of how devastating this parasite is not to just the hobby but to the whole fish farming industry. Any new way of 100% treatment will make headlines! :eek:

13. If the MI can't always be detected, then why bother with a quarantine procedure? In the confines of a small quarantine and being there for no less than 6 weeks, the MI parasite will make itself known because the fish is weakened and the fish can't get away from being re-infected by multiplying MI parasites. In other words, the quarantine procedure instigates a 'bloom' of the parasite which will make it visible to the aquarist.

14. All white nodules fall off the fish and move on to the cyst stage. Untrue. It has been discovered that, on very rare occasions (why we don't know) the white nodule will encyst and rupture while still on the fish.

15. UV and/or Ozone kills MI. Ozone doesn't kill all parasites that pass through the unit, nor does the water treated with ozone kill the parasites. UV only kills the parasites that pass through the unit. Not all MI parasites will pass through the unit, so the UV will not rid an aquarium of MI. A UV can help prevent a 'bloom' of the parasites however, and thus help in its control. UV is not a cure nor a preventative measure for MI. :(

16. Spots are MI. Untrue. Probably one of the most problematic causes for rumors and myth-information in the hobby is assuming the spot is Marine Ich when it may be one of another few dozen other parasites or conditions (e.g., pimple-like reaction to infection) that look like Marine Ich. The mis-diagnosis is often the cause for claims of what cured MI, when the fish didn't have MI to start with.

17. My LFS quarantines their fishes for 2 weeks and I only buy them to be sure they are healthy and free of MI. Have you been reading the above? The 2 weeks is not long enough. Was the 2 weeks in isolation or is the fish's water mixed with other fish's water? Seeing is not believing, right? The truth is out there. . .Trust no one.

18. New reports indicate that there are forms of MI parasites that can survive in low salinity. True. In brackish waters there are variants of the parasite that can live in salinity as low as 5-8 ppt. Then why should we still count upon hyposalinity as a treatment? Easy. The variant in brackish waters is not the variant in natural sea water (35ppt). A marine fish has the MI variant adapted to 35ppt. So when hyposalinity is used on this parasite - it works.

19. The parasite can adapt to low salinity and it can survive a hyposalinity treatment. Highly unlikely. The parasite can adapt. Mother Nature likes to throw genetic variants into the mix when life reproduces. The theory is to give the organism a chance to survive (natural selection) in a changing environment. When the salinity is lowered to about 11-12ppt in the treatment tank, the MI cysts and free-swimming parasites don’t have the time to go through an adjustment. The sudden shift in salinity puts too much stress on the parasite. They are not able to ‘suddenly’ adapt. Remember those parasites that do live in low salinity got there slowly and are not the same ones on our marine fishes. See 18. above.

20. It comes and goes and my fish are fine. Untrue. The parasite doesn't like light. It tends to go through its stages quickly in the dark. Some will develop their white spot at night and drop off before the hobbyist checks the tank. Also, fish can 'hide' the parasite in the display tank by harboring it in their gills. If the parasite was noted there, it is still there. It didn't 'go' anywhere. Hobbyists can and do see spots in the morning and come back at lunch and all the fish are 'clean.' The fish are still sick. REMEMBER you can't see the parasite. All you can see with the unaided eye is the one stage where the spot is large enough to see.




PLEASE DON'T SPREAD RUMORS! :(
 
Last edited:
Not sure if this is even going to let me post questions here, but:

"13. If the MI can't always be detected, then why bother with a quarantine procedure? In the confines of a small quarantine and being there for no less than 6 weeks, the MI parasite will make itself known because the fish is weakened and the fish can't get away from being re-infected by multiplying MI parasites. In other words, the quarantine procedure instigates a 'bloom' of the parasite which will make it visible to the aquarist."

What if the fish is not stressed in the qt tank and water parameters are kept right? I am working on deciding how I can qt animals so they are 99% disease free coming into my tanks. It almost seems to me as some sort of dip would be required. Thoughts?

"16. Spots are MI. Untrue. Probably one of the most problematic causes for rumors and myth-information in the hobby is assuming the spot is Marine Ich when it may be one of another few dozen other parasites or conditions (e.g., pimple-like reaction to infection) that look like Marine Ich. The mis-diagnosis is often the cause for claims of what cured MI, when the fish didn't have MI to start with."

I think this should perhaps be moved up to the top of the list and possibly linked to more information? Perhaps some photos of what it typically looks like? Photos of what it definitely does not look like? Are you aware of any good sites to help visually identify common fish diseases and parasites.

Jon
 
No common dip procedure will cure/rid fish of Marine Ich. I do recommend a dip on all acquired fishes before they go into quarantine. This is the post that contains that: Fish Acclimation Procedure, and then contains links inside that post to the pertinent other information.

Not to worry about 'stress.' The fish mostly came in from the wild and in the confines of a QT there will sufficient stress regardless of what it appears to you. However the prime cause of the MI bloom is the small space of the QT and the single host.

Jon, you can usually Goggle the disease by name and find a lot of photos. I don't count too much on photos alone since many are misleading. The visual part of any disease is only a small part of what it takes to perform a decent diagnosis. Take a look at the short discussion in this short thread: Fish Disease ID.

Thanks for posting.
 
Hey Lee it's me again. Please don't take my questions as just me challenging your word to be annoying. I'm just trying to fully understand the topic. I've also been a science major for a good time and we are taught to question everything.

In number 10 above under treatments you say "10. Let aquarium go fishless...." Something I swore I've heard you say in the past, but have not found it written in the article is what to do with the other fish. If a fish has an outbreak of ich shouldn’t any fish that was in the water with it be treated in one form or another?

“11. NEVER combine a copper treatment with a hyposalinity treatment. In hyposaline solutions, copper can be lethal to marine fishes.” Can you help me find a couple of sources that back up this? I have recently found out that several wholesalers use low salinity as well as copper to combat disease in their holding tanks and are advising LFS to do the same. I am curious to what degree copper becomes increasingly dangerous to the animals with what change in salinity.

Also are there any books you would recommend on fish disease and qt procedures?

Thanks again Lee. I have referred many people to your articles and I am sure Reef Frontiers has several new members just so that they can read your stickys.

Jon
 
Jon,

I appreciate your thoughtfulness in indicating your questions are for additional information as opposed to challenging. I get both. :)

With regards to 10. it shouldn't be taken out of context. See also 3. under Defense and Immunity as an example. All fish need treatment whether they display or not.

With regards to 11. you won't find any back up in literature because for the most part it is not a chemical complication. My recommendation for this is based upon three reasons:
1) Copper med suppliers were loosing money from the hobby because there is a low to no cost cure for Marine Ich. They recommend using both -- they get to sell the med anyway, that way. For the same reason they have cast disparity upon the hyposalinity treatment and allow rumors to fly that hypo doesn't work. I don't want to make them any richer nor cost a hobbyist anymore than they have already spent in this hobby.
2) In a hyposalinity solution, pH is very hard to control. It will take diligence and discipline for the hobbyist to control the pH performing the hyposalinity treatment process. If there is copper in solution, a shift to a lower pH will increase the 'concentration of available copper.' It could push the copper into an active concentration lethal to the fish if it began on the edge of what that particular fish could tolerate. This info on pH and copper exposure you will find in literature. I don't want any fish loss just because the hobbyist lost control of the pH or it shifted down while they were at work. It isn't a salinity concern per se, it's a pH concern. Although the QT is supposedly setup without carbonate substances, we can't ignore the fact that artificial sea water contains carbonates which will tie-up some copper, the quantity of which is relative to the pH of the liquid.
3) Not all medications behave the same. In different water salinity, some meds are poisons, others may be rendered unable to perform. The same may be true of some copper meds. There are so many out there and in different countries, different supplies, as well as homemade meds. I have to write for the whole. Only the manufacturer of the med knows for sure whether the med is safe with hyposalinity treatments. Unfortunately, relative to 1) a hobbyist may be misled into believe both are necessary.

Hope the above helps. Thanks for your referrals. I hope they encourage good marine husbandry in this hobby. :D
 
Hello Gentlemen;

I have found through the years that a fresh water dip 1.004 sg of a fish heavily infested with signs of labored breathing/slime does seem to give some comfort to fish. I have also noticed that a lot of the slime drops off the fish and now is in the dip container.

I use Iodine (medicinal) in my fresh water dip water to help with any bacteria infection. I leave the fish in this dip until real signs of stress develop or 30-minutes.

I QT infected fish for extended periods as reported by some up to 8-weeks in the hospital tank. I have reason to believe that this QT in hypo-salinity 1.010 sg also kills other organisms that infest marine fish through practical experience.

A good article:
----------------------------------------------------------------------------------
http://www.reefkeeping.com/issues/2003-08/sp/index.php
----------------------------------------------------------------------------------

In my experience if left untreated, Ick kills eventually. Also, in my opinion a marine tank can be totally free of the parasite.

I offer advice on hypo-salinity only, copper is a proven method of treatment but I have serious doubt that many new to the hobby can test and maintain the proper levels for extended periods. Furthermore, I think the temptation of 10-drops is good, 20-may be better is too high for some. And as you Gentlemen have pointed out Copper is a TOXIN.

------------------------------------------------------------------------
"I like my unsubstantiated biased opinion better than your proven scientific facts!"

"OFM"
------------------------------------------------------------------------

Enjoy!


OFM
 
Last edited:
I've read this a few times, and I'm not sure I understand:

"14. INTERESTING FIND: If no new MI is introduce into an infected aquarium, the MI already there continues to cycle through multiple generations until about 10 to 11 months when the MI has ‘worn itself out’ and becomes less infective. A tank can be free of an MI infestation if it is never exposed to new MI parasites for over 11 months."

Removing the "new MI" from this still leaves the original MI in my tank for 10-11 months when it becomes less infective? This contradicts the recommended 8 weeks fallow instruction doesn't it? I'm assuming I am missing the point in here...

thanks!
 
Reread the life cycle again. There is no doubt that crypto won't be able to reproduce with out a fish host. After 8 weeks of a fish less system there will be no ich. After 11 months in a system with fish and with no new crypo introduced the tank will be clear.

Pretty much I would ignore that little tid bit of information about 10-11 months and consider it a mute point you don't need to understand. Just reread the rest of it three times and take it as the bible and you'll be fine.
 
No. Fish 'flash' or scratch themselves because there is an irritation. There are dozens if not hundreds of ways a fish can be irritated which would cause it to flash. However, flashing is one of the symtoms of Marine Ich.

The diagnosis is to look for the spots and a group of symptoms. The spots are most reliable in diagnosis.
 
Status
Not open for further replies.

Latest posts

Back
Top