How long to go Fallow?

[00101]

So I've set up my new tank, and I put a bunch of corals in from a swap, so I have things from a bunch of different reefers from hobbyist to commercial. I also have gotten a new fish that has been kept in a separate tank up until now. I want to do my best with quarantine procedures for this new tank. How long do I have to keep the fish out of the DT to ensure that any parasites that hitchhiked on the corals will have died out?

Fish will be receiving 2 rounds of prazipro, and likely TTM in the meantime. Is there anything else I ought to do? Fish appears to be in good health or is asymptomatic.

[lg2725]

Taking it into regard from someone brand new in this but from what I have read, DT stays fallow for 72 days (minimum) after ANYTHING other than a QT'd fish goes in. That includes corals and inverts. I'm in the process as we speak. I am sure someone with more experience will post.
Happy Reefing!

[Deinonych]

Originally Posted by lg2725

Taking it into regard from someone brand new in this but from what I have read, DT stays fallow for 72 days (minimum) after ANYTHING other than a QT'd fish goes in. That includes corals and inverts. I'm in the process as we speak. I am sure someone with more experience will post.
Happy Reefing!

Correct.

[00101]

Yeesh. Was hoping for something closer to a month. As always I assume its an all or nothing proposition? Either I'm sure its gone, or I'm sure its there?

[ThRoewer]

72 days is only the longest observed duration of a cyst - you still have to add a day or two for the hatched infective stages.
So the minimum fallow based on this should be 74 days.
Though if you go that long you may as well do 3 full months - keep in mind that this was a single observation of a single strain. There is no warranty that a cyst can't hold out longer.

[00101]

So where does the 72 day figure come from? I've been doing some searches through my university's system and I'm not really finding a whole lot of specific details about the cyst stage.

[Mishri]

Interesting.. I usually see people cite this study for the 72 day window

http://www.int-res.com/articles/dao/1/d001p019.pdf

but.. I read it says 28 days is maximum... must have been from a different study. I seem to remember reading it before, and it was done by keeping it at something like 52 degrees... the ones kept at normal aquarium temps all hatched much sooner... and even to achieve 25-28 days they kept it at low salinity.


just keep in mind the time/money/fish lives you could lose if you decide to shorten it though. I'll be doing a 90 day fallow period on my currently ich infected tanks. patience is very inexpensive...

[00101]

Originally Posted by Mishri

Interesting.. I usually see people cite this study for the 72 day window

http://www.int-res.com/articles/dao/1/d001p019.pdf

but.. I read it says 28 days is maximum... must have been from a different study. I seem to remember reading it before, and it was done by keeping it at something like 52 degrees... the ones kept at normal aquarium temps all hatched much sooner... and even to achieve 25-28 days they kept it at low salinity.


just keep in mind the time/money/fish lives you could lose if you decide to shorten it though. I'll be doing a 90 day fallow period on my currently ich infected tanks. patience is very inexpensive...

Hmm. Interesting. I'm all for doing the job right, but there's a difference between doing it right and doing 3x as much for no reason. The articles I've read so far mostly deal with vaccination and protocols for keeping infections to a minimum in mariculture facilities.

I don't want to disparage the experts or anything, but like many things both in and out of the hobby it might be a case of 'so and so said to so thats what I do..." ad infinitum.

[Deinonych]

Originally Posted by Mishri

Interesting.. I usually see people cite this study for the 72 day window

http://www.int-res.com/articles/dao/1/d001p019.pdf

but.. I read it says 28 days is maximum... must have been from a different study. I seem to remember reading it before, and it was done by keeping it at something like 52 degrees... the ones kept at normal aquarium temps all hatched much sooner... and even to achieve 25-28 days they kept it at low salinity.


just keep in mind the time/money/fish lives you could lose if you decide to shorten it though. I'll be doing a 90 day fallow period on my currently ich infected tanks. patience is very inexpensive...

There was a more recent study (1997) by the same author (along with P. Burgess) in which the 72-day period was observed in at least one strain. I have a PDF archived somewhere, but can't find an online source that doesn't require payment. Here's the abstract: http://link.springer.com/article/10....:1018360323287

[Mishri]

This one has a bunch of studies cited you could read through:

http://edis.ifas.ufl.edu/fa164

this is cited frequently.. for data on ich


I think that link Is the one you are referencing Deinonych

edit: maybe it isn't.. I can't find the section which would have that info in it.. I think it still says 21 days on that one.. but I know someone did link me to a study that had the 72 day observation in it.. because nobody else could find that info either.. this has been discussed before as I wanted that info as well. The thing I still had a problem with though was the temp was so cold to keep it as a tomont/cyst stage longer intentionally... so it isn't what we would observe under normal reef aquarium conditions. But, there are new strains being discovered and one that can survive hypo so... things are getting tough. I doubt that any strains are developing longer rather than shorter tomont duration though.. I can't imagine the benefit for it.

edit again: this should hit a pdf:

https://pearl.plymouth.ac.uk/bitstre...PDF?sequence=1

[Deinonych]

Originally Posted by Mishri

edit again: this should hit a pdf:

https://pearl.plymouth.ac.uk/bitstre...PDF?sequence=1

That's the one. Good find.

The University of Florida one you mentioned above is also very good as it provides all the pertinent information about Cryptocaryon in one place (and in relatively lay language).

[microlady]

72 days worked for me.

[traumamed]

I am currently in the midst of a fallow period in my DT for velvet, so I have just done a bunch of research on fallow periods myself. The advice above is absolutely sound, but I will offer a different way of looking at things.

This is an odds game, and on multiple levels. The odds that your new livestock was infested, the odds that it is infested with ich vs velvet (shorter life cycle) vs something else, and the odds that it is a long-lived tomont strain of whatever the hypothetical infestation may be. So it more boils down to your comfort level and how risk-averse you are.

Go 72-74 days, and you're pretty much guaranteed a parasite-free tank. That will cover the longest-lived strains of the longest-lived saltwater parasites under water conditions that are conducive to longevity of parasites.

However, many people will green light new livestock for the DT after only 4 asymptomatic weeks in a QT. For that matter, many people don't QT at all and get lucky most of the time, but that is not good husbandry.

I need to dig up the source, but I saw one article that said something like 84% chance of being parasite-free at 4 weeks fallow, 97ish % at 6 weeks, and 99.7% at 8 weeks. Can't remember where or in reference to what though, but my gut is telling me that was for marine ich. The data is out there (and referenced in the posts above). You have to decide what level of risk, if any, suits you.

[ThRoewer]

Originally Posted by microlady

72 days worked for me.

... and only 4 weeks worked for me... (with 4 fully immune fish still in the tank) - no new fish ever got it.

The tomonts of most ich strains will likely be excysted after the 28 days as stated in the above linked Colorni study.

The 72 days go back to one single observation in one single study among several research studies done on Cryptocaryon. From hearsay here, this was also under rather fringe conditions (rather low temperature).
Based on that it is nearly impossible to claim that 72 days is the maximum encystment period or to claim that this is a frequent occurrence.

I would bet that in most cases 42 days would be more than sufficient.
Yet, there are also indicators that there are strains that may hold out longer.

So in the end there is no way to say how long is enough, only that the longer you go the better your odds get.
After 90 days your chances of being ich free are pretty good, though 30 may already be enough.

[00101]

Originally Posted by traumamed

I need to dig up the source, but I saw one article that said something like 84% chance of being parasite-free at 4 weeks fallow, 97ish % at 6 weeks, and 99.7% at 8 weeks. Can't remember where or in reference to what though, but my gut is telling me that was for marine ich. The data is out there (and referenced in the posts above). You have to decide what level of risk, if any, suits you.

Was that one of stickies by snorvich? Because the numbers he showed there were entirely hypothetical to show how a normal distribution worked. He said right in it that no one really knows the actual distribution characteristics of the cysts.

Edit: http://reefcentral.com/forums/showthread.php?t=2388421 This one? Because "Unfortunately, there is no published value for the standard deviation of the life cycle of Cryptocaryon irritans."

Also being that this uses the life cycle mean, I'm suspect if that is even the figure we want to be examining. More directly when going fallow, we really only care about how long the cysts can remain viable.

[ThRoewer]

Well, if you remove your fish from an ich infested tank and return them 72 days later and happen to have a cyst (tomont) that lasted 72 days, your fallow period would have failed.

What is mostly ignored are the protomont (up to 18h) stage and tomite (up to 48h) stages These add roughly 3 days to the possible 72 day tomont duration for the required fallow period.

So if you assume that 72 days is the longest a cyst can hold out you would need to wait 75 days before returning the fish.

[traumamed]

This has just about everything you'd ever want to know about Cryptocaryon. It references the 1997 Colorni and Burgess study that showed the infamous 72-day tomont, but it also discusses the average lengths of time before tomont-to-theront progression based on both Colorni and Burgess 1997, and on Diggles and Lester 1996.

[00101]

Originally Posted by traumamed

This has just about everything you'd ever want to know about Cryptocaryon. It references the 1997 Colorni and Burgess study that showed the infamous 72-day tomont, but it also discusses the average lengths of time before tomont-to-theront progression based on both Colorni and Burgess 1997, and on Diggles and Lester 1996.

Alright so I've done some digging! The 1997 study from Colorni and Burgess cites the 72 day figure coming from Colorni 1992 which from what I can tell is an unpublished thesis. The only place that I have found that hosts this paper is the Hebrew University of Jerusalem (the university where the work was done). I don't think I'm able to gain access to the full text, so I cannot examine the data or experimental conditions. I suppose I could contact the HUJI library to see if they'd send me a copy, but as this has nothing to do with my research or anything I don't know how successful that would be.

The 1996 study by Diggles and Lester does not offer any data of tomont excystment past 15 days, other than around half had done so by that point. This study also hypothesizes that excystment times varied so significantly between the two isolates because of the local conditions of where the isolate is from, with the isolate obtained from tropical reef water taking longer to excyst at their 20C and 25C conditions than the the isolate from cooler waters. So there's a significant variable that we don't have anyway of actually nailing down. I would hazard that most ciliates in our tanks come from tropical waters, but with how many different fish are coming from all over the world and being handled who knows where, its hard to say for certain.

Now where does this leave us? I don't know. Without the 1992 thesis, there's really no way to accurately interpret the data and apply it to our reef tanks. Especially since I hear many who talk about this figure saying that the 72 days was accomplished with lower temperatures and/or salinity. Which the Diggles and Lester study showed significantly impacts excystment times.

[microlady]

I stand corrected. 72 days did not work for me. New fish added are showing ich, and yes they were quarantined properly. It must still be in my display.

[danrobberg]

That is the last thing I wanted to read. I am 4 weeks into my fallow period. Looks like I'm going the full 90 days.

[CrayolaViolence]

I went twelve weeks and a few days. Fish were QTd and clear when they entered the tank. Within 2 weeks they had ich.

I honesty don't think there is an answer.

Correction: I was thinking 12 weeks, but it was actually 3 almost 3.5 months. A loooong time. Way more than people said I needed. Still wound up with sick fish after QT

[danrobberg]

Ok that's even worse to hear.

[danrobberg]

During your qt did you treat with copper?

[microlady]

I went 72 days the first time and 90 the second. Fallow periods work well for knocking down the virulence of the parasite, but in my experience it doesn't eliminate them. I am really sick to my stomach when I think about all that I've went through the past year. All of my fish went through TTM a few times. I don't touch copper.

Two of my dwarf Angels show a few spots and my tang scratches sometimes. So far it doesn't seem too bad. Only time will tell.

Good luck.

[ThRoewer]

I killed it of in my 42 gallon tank by leaving the immune fish in the tank and only treating the very sick regal angels. No new fish I added to that tank ever showed a spot, and this tank is not only heavily stocked but has also a bit bullying going on.
I have the suspicion that at least some ich strains might have long term cysts in hibernation which wake up when they "smell" a fish near by.

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