Fallow period for cryptocaryon irritans (ich)

[SueAndHerZoo]

one more quick question...Is it OK to introduce fish to a QT being treated with cupramine? I just got an order of fish from LA and one of the anthias was dead and needs to be replaced. they said i should wait out the 14-day guarantee on the other fish as they'll only reship one time for the order so i won't get the other anthias for a couple weeks. i don't really want to delay the treatment of the fish i do have. any issues here? i plan on treating for around 5 weeks so the new guy would come into an ich-free tank and then be treated for 3 weeks.

I asked the same (or similar) question about 6 weeks ago.... to read the answers I received (all good answers, btw) here's the thread:

http://reefcentral.com/forums/showthread.php?t=2134203

And I'm with you.... I would gladly have paid $500 for a safe and easy solution to this problem. Unfortunately, I don't think there will ever be such a thing. Some things, money can't buy.
Sue

 

[jlylec]

I asked the same (or similar) question about 6 weeks ago.... to read the answers I received (all good answers, btw) here's the thread:

http://reefcentral.com/forums/showthread.php?t=2134203

And I'm with you.... I would gladly have paid $500 for a safe and easy solution to this problem. Unfortunately, I don't think there will ever be such a thing. Some things, money can't buy.
Sue

thank you very much for this! sounds like i'm in a bit of a pickle too. i have sand in my QT. that's probably why I had a hard time keeping the Cu level up before. I didn't realize it absorbed the Cu. ugh. I hope I got all the ich out of my original fish before putting them back in the DT! I'm on my second round of fish in QT now. I'm going to wait until they're fully treated and in the DT before buying any other. Sounds like that's the way to go. Thanks again!

 

[snorvich]

one more quick question...Is it OK to introduce fish to a QT being treated with cupramine? I just got an order of fish from LA and one of the anthias was dead and needs to be replaced. they said i should wait out the 14-day guarantee on the other fish as they'll only reship one time for the order so i won't get the other anthias for a couple weeks. i don't really want to delay the treatment of the fish i do have. any issues here? i plan on treating for around 5 weeks so the new guy would come into an ich-free tank and then be treated for 3 weeks.

Adding fish to quarantine restarts the clock. (hypo or cupramine)

 

[joegoersch]

A littl e mathematical correction

A littl e mathematical correction

A normal distribution is a very important statistical data distribution pattern occurring in many natural phenomena, such as height, longevity of a member of a population e.g. human being.s For this discussion we are focused on the life cycle of Cryptocaryon irritans, otherwise known as marine ich. Certain data, when graphed as a histogram (data on the horizontal axis, amount of data on the vertical axis), creates a bell-shaped curve known as a normal curve, or normal distribution.

Normal distributions are symmetrical with a single central peak at the mean (average) of the data. The shape of the curve is described as bell-shaped with the graph falling off evenly on either side of the mean. Fifty percent of the distribution lies to the left of the mean and fifty percent lies to the right of the mean. The average life cycle of Cryptocaryon irritans is 3 weeks.

The spread of a normal distribution is controlled by the standard deviation. The smaller the standard deviation the more concentrated the data. Unfortunately, there is no published value for the standard deviation of the life cycle of Cryptocaryon irritans.

If you look at the percentages of population members within a standard deviation of the mean, we see that approximately 19.1% of normally distributed data is located between the mean (the peak) and 0.5 standard deviations to the right (or left) of the mean. For Cryptocaryon irritans, we are going to assume that 68% of the members lie within one standard deviation of the mean.

If you add percentages, you will see that approximately:
"¢ 68% of the distribution lies within one standard deviation of the mean.
"¢ 95% of the distribution lies within two standard deviations of the mean.
"¢ 99.7% of the distribution lies within three standard deviations of the mean.

These percentages are known as the "empirical rule". What this means for Cryptocaryon irritans is that leaving a tank fallow for 3 weeks will give you a 68% chance that you have eradicated the parasite, leaving a tank fallow for 6 weeks will give you a 95% chance of eradication, but if you want 99.7% chance, you will leave the tank fallow for 9 weeks. That is the reason you see different numbers being used on Reef Central and in the literature.

I see confusion when different numbers are used for the required fallow period to make sure you tank is ich free. Perhaps this will clarify. Or not!

I want to thank you for all your help. I believe your conclusions may be correct, but as a math major I just want to correct some of the statistics here which aren't quite right.

If the life expectancy of a single cyst is what's being considered than you are almost right. If you wait two standard deviations than 97.5% of the time, the cyst will die. It's not 95% because of the 5% that doesn't die within +/-2 standard deviations, half (2.5%) will die sooner and half (2.5%) will die later.

But rarely I would think is one concerned about a single cyst in an infected tank. We are probably worried about hundreds (thousands ?). If you had three cysts the odds of all dying in two standard deviations would be 97.5% *97.5%*97.5% or 0.975*0.975*0.975=92%. In general for n cysts the chace of all dying would be 0.975^n. For 10 cysts about 77%.

But I don't think life expectancies follow a bell curve exactly. (they can't since you can't die before zero).

What would be great to know is what percent of people have had a reinfection after 6,8, 10 weeks ? What is the standard deviation of success ? E.g. if you leave you tank fallow for how many weeks do you stand a 68%, 95%, 99.7% etc chance of success ?

Has anyone left a tank fallow for 8 weeks and had a problem with reinfection that wasn't due to a mistake (like using a contaminated bucket)?

Thanks again, and please realize I am just pointing out a mathematical issue and know very little about Ich. You do and I thank you for sharing !:rollface:!!

 

[snorvich]

I was simply trying to keep it simple as there are a huge number of variables involved and I was simply trying to provide a structural framework for making intelligent decisions. For example, salinity, temperature, and cryptocaryon irritans strain, unfortunately all come into play. And of course we are forced to infer population statistics from a very limited sample size of which hard numbers are not available.

 

[snorvich]

But rarely I would think is one concerned about a single cyst in an infected tank.

Actually you are. Since a single cyst can produce up to 200 tomites, this restarts the life cycle

Has anyone left a tank fallow for 8 weeks and had a problem with reinfection that wasn't due to a mistake (like using a contaminated bucket)?

Impossible to know with anecdotal experience. Unfortunately we are never presented with accurate structure around anecdotal episodes and rarely are we even presented with enough to diagnose why

Thanks again, and please realize I am just pointing out a mathematical issue

Yes, I know.

and know very little about Ich. You do and I thank you for sharing !:rollface:!!

 

[mcola78]

When you refer to the tank being "fallow" do inverts count or not? I just had the ich issue so removed fish but have a ton of inverts (snails, crabs, shrimp) in tank. Do they count or can I go the 10 weeks with them still in the tank and assume good to go after?

 

[snorvich]

When you refer to the tank being "fallow" do inverts count or not? I just had the ich issue so removed fish but have a ton of inverts (snails, crabs, shrimp) in tank. Do they count or can I go the 10 weeks with them still in the tank and assume good to go after?

Inverts are fine as they are unable to "host" any stage of the parasite.

 

[Seagars]

Is it possible for ich to live dormant in the frozen food we put in our tanks? this thought just occurred to me as I read this thread. I just got through a 12-week fallow period in my DT and treating my surviving fish with cupramine for a month and observing for another and treating with prazipro. taking NO chances! it would be so depressing to have another outbreak!

I wish I were smart enough and had the time to work on a cure for ich (although I'm sure many have already tried). I have a feeling you'd be a millionaire pretty quickly if you came up with a reef-safe treatment. I would have paid $500 (maybe more at this point!) to be able to treat my DT without catching all the fish and running fallow for 12 weeks!

was thinking the same thing.. then i could build the biggest tank i wanted where ever i wanted.

 

[Bubbs6960]

Ich Question

Ich Question

My tank got ich and it slowly one by one kill all my fish. I have a small 29 galllon biocube. There is 30 lbs of live rock in the tank and 4 dwarf red tip hermit crabs and 4 Nerite snails left in my tank. I understand the tank needs to be fallow for 8 weeks for the Ich parasite to die. 5 Questions. Can the snails and hermit crabs keep the Ich alive? Should I get rid of the if they are able to keep the ick alive? During the 8 weeks I asume I keep the pumps and filters running, but do I also keep the lights comming on and off? and last do I need to treat the tank with anything during the 8 weeks or do I just monitor the PH, Nitrites, ect? I read about Hypersalinity, is this anything that since the tank is empty would help? I sorry for so many questions, but I'm a newbie and you look like you all know whats going on. Thanks for you help. :spin1::spin1:

 

[snorvich]

My tank got ich and it slowly one by one kill all my fish. I have a small 29 galllon biocube. There is 30 lbs of live rock in the tank and 4 dwarf red tip hermit crabs and 4 Nerite snails left in my tank. I understand the tank needs to be fallow for 8 weeks for the Ich parasite to die. 5 Questions. Can the snails and hermit crabs keep the Ich alive? Should I get rid of the if they are able to keep the ick alive? During the 8 weeks I asume I keep the pumps and filters running, but do I also keep the lights comming on and off? and last do I need to treat the tank with anything during the 8 weeks or do I just monitor the PH, Nitrites, ect? I read about Hypersalinity, is this anything that since the tank is empty would help? I sorry for so many questions, but I'm a newbie and you look like you all know whats going on. Thanks for you help. :spin1::spin1:

Nine weeks fallow. Only fish need be removed. If you have hermits, etc, feed them lightly.

 

[RIGUY314]

hello - quick question - My DT is in the Fallow period (about 2 weeks in) as my tank was almost completely wiped out from ich. DT has inverts and the last fish is in QT doing well. wanted to know if I could add a piece of live rock to the DT tank. It was such a unique piece I put it on hold at the LFS. thanks

 

[snorvich]

hello - quick question - My DT is in the Fallow period (about 2 weeks in) as my tank was almost completely wiped out from ich. DT has inverts and the last fish is in QT doing well. wanted to know if I could add a piece of live rock to the DT tank. It was such a unique piece I put it on hold at the LFS. thanks

No problem at all.

 

[RIGUY314]

No problem at all.

thanks for the reply! appreciate it.

 

[Patrick12]

My tank got ich and it slowly one by one kill all my fish. I have a small 29 galllon biocube. There is 30 lbs of live rock in the tank and 4 dwarf red tip hermit crabs and 4 Nerite snails left in my tank. I understand the tank needs to be fallow for 8 weeks for the Ich parasite to die. 5 Questions. Can the snails and hermit crabs keep the Ich alive? Should I get rid of the if they are able to keep the ick alive? During the 8 weeks I asume I keep the pumps and filters running, but do I also keep the lights comming on and off? and last do I need to treat the tank with anything during the 8 weeks or do I just monitor the PH, Nitrites, ect? I read about Hypersalinity, is this anything that since the tank is empty would help? I sorry for so many questions, but I'm a newbie and you look like you all know whats going on. Thanks for you help. :spin1::spin1:

Inverts cannot "keep ick alive". Only fish. It is an integral part of the lifecycle. In fact, once the tomont hatches and releases the theronts.....they have 18 to 48 hours.....most all have about 24 +/- 2 hours to find a fish host or die. Temperature DOES affect how long the theronts can survive without a host according to research studies.

I'd recommend a normal light cycle...but it should not matter. There is one study that actually examined this very aspect and while there were some minor differences it was not statistically significant as I recall. But, other research tends to indicate that the tomonts prefer to excyst and release theronts at dusk and at dawn.....so keeping as many day night cycles as possible during the fallow period would seem to make sense and give more stimuli to encourage excystment without fish present. The study di not indicate if it was a time thing or a light thing so not sure what stimulates excystment.....time or light/lack of light.

Certainly keep the filters running.....in fact do what you normally do to the tank in regards to maintenance etc during the fallow period. Some suggest siphoning the gravel with water changes as a possible means of incidentally extracting tomonts........personally I find this on the lowest end of affecting anything with regards to crypt. But, it might make you feel like you are doing something.

I'd recommend against adjusting the salinity in your fallow aquarium whatsoever. There is indications that the parasite reacts to drastic changes in salinity and this can alter its excystment time. So for that reason I'd just leave the tank as is and fallow for the period of time recommended or you feel best. I personally have used 6 weeks on my own systems in the past and on several fellow reefers aquariums when helping them and never had a relapse. But, as an exercise in statistics.....I see the 9 weeks and find no fault in it. If 6 weeks is good, 9 weeks can only be better. The only relapse I have had with crypt was using hyposalinity....wasn't bad fish were pulled and coppered and all lived.....but hypo is no longer a fan favorite of mine. Also, in the interest of full disclosure I DO RAISE TEMPERATURE. This has become a recent debate, but the earliest studies indicated that temperature did effect the metabolism of the parasite and the mariculture studies certainly had a different time from encystment to excystment at lower temps. I raise my temp in the fallow period to 82-84F for the fallow period. Temps that high should not cause any healthy corals to be effected.....but you can reduce the photoperiod for an couple hours to offset any metabolic effects on the corals if concerned.

Best of luck. Crypt is the number one reason for good QT procedures....but there are several others. If you have not dealt with this parasite you are lucky and have likely not been in long. It is just too prevalent now in most the LFS and supply chain wholesalers.

 

[snorvich]

Excellent post above.

 

[saltyjarhead]

When you refer to the tank being "fallow" do inverts count or not? I just had the ich issue so removed fish but have a ton of inverts (snails, crabs, shrimp) in tank. Do they count or can I go the 10 weeks with them still in the tank and assume good to go after?

Was just going to ask the same question thanks for asking it for me. I have snails and hermits in my tank now and wanted to add a cleaner shrimp as long as it didn't affect my fallow period.

 

[jlylec]

Fallow means fish free. Inverts (snails, crabs, shrimp) don't carry ich. That was the first line of the post like 3 up from this!

To the question about adding the LR...this is OK, but you should reset your fallow clock as ich CAN survive and be introduced on LR from a LFS.

 

[saltyjarhead]

Fallow means fish free. Inverts (snails, crabs, shrimp) don't carry ich. That was the first line of the post like 3 up from this!

To the question about adding the LR...this is OK, but you should reset your fallow clock as ich CAN survive and be introduced on LR from a LFS.

Right that's why I said thanks for asking the question and the answer was there for me already.

 

[snorvich]

To the question about adding the LR...this is OK, but you should reset your fallow clock as ich CAN survive and be introduced on LR from a LFS.

This is technically true. However unless this rock was stored in a system containing fish (directly or inferentially through shared water) it should be safe. However, NEVER share water from transport from an LFS.