Why a fallow period will sometimes fail

[Humblefish]

Thanks for adding this part. I agree that it would be the exception. Also, tangentially, have you seen this paper?
https://www.researchgate.net/public...f_the_ciliate_protozoan_Cryptocaryon_irritans

Bookmarked! Will read soon.

 

[Humblefish]

I have a sump (slightly covered) should I fully uncover? Everything running as normal. Return pumps power heads skimmer etc.... Bare bottom tank. I should be good right? I'm about 2 weeks into fallow. All QT and other aquariums are appx 12' away.

@Humblefish

I would run a small powerhead in your sump and also blow out your rocks using a powerhead. For good measure.

 

[Tamberav]

Just when I was thinking about jumping on the QT train lol. I'm seriously considering just purchasing all captive bred fish at this point...

My friend just got into the hobby and I spared him the disease problems and told him to buy captive bred fish shipped directly from ORA. No complaints!

 

[PDR]

My friend just got into the hobby and I spared him the disease problems and told him to buy captive bred fish shipped directly from ORA. No complaints!

My post was meant slightly in jest, but I have been drawn to captive bred fish lately. I think getting them directly from the breeder before they enter into the distribution system is key. In a recent interview, ORA mentioned some future fish they are working on and mentioned tangs, angels, and wrasses. That would be very exciting if we could start to get more of those type of fish captive bred!

 

[MnFish1]

How can I setup my Display Tank to be "hypoxic proof" just in case I ever have to go fallow?

this was very interesting. unfortunately here is no way to eliminate all hypoxic areas in a tank..... on the other hand just because something 'can happen' doesn't mean it happens often.... lots of people leave their tanks fallow and have no problem. frankly I thin this article may explainain some failures - but is probably not likely,,,, I can't read the methods of how they did this - but I think its unlikely to happen in our tanks. jmo

 

[chicago]

nice write up. In my copper system.. this might sound strange.. but similar situation...i noticed when my deep sand bed if stirred up...had some ick emerge

 

[Ferrell]

Great info as always

 

[Cmccarthy]

That’s it...back to freshwater.....hahaha

 

[Fowler freak]

We've all seen claims of ich, velvet, etc. returning after a 76 day fallow period. (For anyone wondering what a fallow period means click here: https://www.reef2reef.com/threads/fallow-periods-going-fishless.190324/)

Oftentimes, a fallow period failure is due to human error: The sick fish weren't treated long enough or the treatment itself wasn't done properly, cross contamination via wet hands or equipment, aerosol transmission (more info). It is also possible that undiscovered strains of ich (and other diseases) exist; ones with a prolonged life cycle that exceeds what we know to be true from scientific research. However, there is also this possibility to consider:

Dormancy induced by a hypoxic environment in tomonts of Cryptocaryon irritans, a parasitic ciliate of marine teleosts


Highlights from the study:

• This study demonstrates that tomonts of Cryptocaryon irritans become dormant in hypoxic environments.
• Dormant tomonts resume development in oxic environments at any developmental stages.
• We examined tomont viability following variable sequences of oxic and hypoxic conditions.
• Dormancy in hypoxic environments may be key to the autumn outbreaks of cryptocaryoniasis in floating net cages in temperate waters.

So what does this mean for us and our fallow aquariums? Primarily, the study showed that an ich tomont (the "egg stage" which encysts to corals, inverts, rocks, etc.) can go dormant if the protomont crawls into a hypoxic (low oxygen) environment or anaerobic (no oxygen) region of your DT just before encysting. Examples of this include under your sand bed (especially a DSB), inside a non-porous rock, any "no flow" region of a canister or other aquarium filter. The study also demonstrated that once returned to an oxygen rich environment, these once dormant tomonts resumed their development and released theronts (free swimmers which seek out fish to infect.) How long can it take for a dormant tomont in a hypoxic environment to suddenly be exposed to an oxic (oxygen rich) environment? The world may never know?!

So what can you do to eliminate low oxygen areas of your DT during a fallow period?

1. Take any canister or enclosed filters offline, and sterilize them with bleach. Without fish to foul the water, your DT will be fine with just rock/sand for filtration and good water circulation.
2. Speaking of circulation, crank up those pumps for maximum flow & gas exchange throughout the aquarium. (Don't forget to add a pump down in the sump.)
3. Blow out your rocks (using a powerhead) and vacuum the sand during water changes whilst going fallow. This will "stir things up" and provide free oxygen to those areas.

How can I setup my Display Tank to be "hypoxic proof" just in case I ever have to go fallow?

1. Only use filtration with an open top (like a sump), and avoid canister filters and other filters which may contain anaerobic regions. If needed, take these offline if ever having to go fallow.
2. Use just a light layer of sand; the deeper it is the more likely tomonts can get "trapped" down under there.
   
3. Never have sand out of reach (i.e. under a rock) in case you need to vacuum it during a fallow period.
   
4. Only use very porous rock which will allow plenty of flow (and oxygen) to pass through.

More information on Marine Ich (Cryptocaryon irritans) can be found here: https://www.reef2reef.com/threads/ich-cryptocaryon-irritans.191226/

Awful news and that just made things that much more complicated than they already are
Thank you for the great write up as always sensae

 

[JumboShrimp]

I try to read everything @Humblefish writes— thanks for your efforts in all of our behalfs!

 

[Cyricdark]

Just when I was thinking about jumping on the QT train lol. I'm seriously considering just purchasing all captive bred fish at this point...

Absolutely Still jump ON the QT train. If you properly Quarantine you will never need the fallow period So this won't matter.

 

[MnFish1]

Absolutely Still jump ON the QT train. If you properly Quarantine you will never need the fallow period So this won't matter.

Unless there are anaerobic areas in your qt tank.

 

[JasonK84]

Knowledge= Success in this (or any) hobby.

Thanks for improving our chances of success.

 

[Goby-won]

Holy cow (or ich) this explains a lot. I had an ich breakout - 14 fish died. I went fallow for way longer than required. Quarantined then started afresh and BAM - ich again....

I have now given in. I follow @Paul B . Throw em in and winner take all. I feed a variety of food - I have one tang - and a bunch of wrasses. I pray for the best, but expect the worst. I do not feel good about this, but either I do this or I worry extensively that I may have just killed everything by adding that last fish.

 

[drawman]

Great read and writeup Humble!

 

[Converted to Saltwater]

Ok so I'm new at saltwater and this was am interesting article thread to me. When I was breeding discus a few years ago I always went fallow for only a week, kept lights dim, then increased temp and with a clean tank always or most of the time anyway if from good stock had success breading. Am I understanding correctly that this is a common occurance in marine aquariums to prevent disease and if so how to judge when and how often?

 

[chicago]

Just saw today one of my QT inhabitants... Diamond Gobbie ... although pair has been in here for like 45 days .. he did a scratch thing on the bottom of the tank.. not sure if ICK still there.. but you can see in the pic.. the tub of gravel i keep in my Copper QT. I have put through a number of fish in this copper system... 55 gallon... I then did these two diamonds and have noticed some continuing signs of ICK.. no visible white spots.. just scratch here and there... I believe related to the constant digging deeper and deeper into the bed...
Years ago when I kept deep sand bed in a 100 gallon back in the 80's (fish only system that i only did water changes like 6 or 4 times a year) I would notice if i stirred up the gravel bed I would have visible signs of ICK on my tangs soon after..

 

[Reefahholic]

Unless there are anaerobic areas in your qt tank.

Not in my QT. Which areas are you referring to?

 

[MnFish1]

Not in my QT. Which areas are you referring to?

The problem is that 'anaerobic areas' dont have to be big. They can be microscopic. (which Is why @Humblefish recommended bleaching cannister filters, etc) I.e. lets say you have a sponge filter - there can be areas in that filter that are anaerobic. Lets say you have a small piece of rock - there can be anaerobic areas in that rock etc etc. It may not be as likely as in a display - but its also not impossible. If you're using copper I think it would be very unlikely (in your QT.

BTW - having read the article - it is different than leaving a tank fallow - so I think even in a display tank this would be an extremely rare occurrence. In other words - its not like anyone has 'disproven' the original studies that show that CI will not survive beyond 76 days in a natural environment:

In the study - they took CI and put them under anaerobic conditions and showed that they were able to survive in a dormant state. There is very little likelyhnood that CI would seek out an anaerobic area in the tank in which to rest (in the study - they didnt have a choice). There might be a random one that lands in such a spot but given the infectivity rate of CI - after a fallow period its very unlikely that a few CI would infect a tank. The goal of CI is to reproduce - there is no reason from a parasitology perspective to think they would seek out an anaerobic area in your tank.

However, that said - I agree completely - that if you're using filters like canisters, or anaerobic denigrators with active flow (i.e. would catch CI from the water column and trap them in an anaerobic area - this could be a problem since the concentration would be much higher IF that area became 'aerobic' again. Even then - the only way such a filter would become 'aerobic' is with cleaning. Sand I guess is another story - and I would think this would be one of he biggest possibilities for this to occur.

 

[4FordFamily]

I think the reports of "ich" being stirred up by stirring up the sand is due to the following:

1) The dirtier water resulting from the sand disturbance stresses fish out and ich (already present) gets the upper-hand

and, perhaps even

2) Often when we are disturbing the sand, we are doing some heavy duty cleaning, moving a tank, etc-- this stress event gives ich that was already present, the upper hand due to dirtier water and fish stress

I tend to agree that this probably doesn't happen a lot, but we should follow these best practices to reduce the liklihood of this happening.

I've failed fallow periods/treatments in many ways:
1) A tiny fish I thought dead was discovered in the sump afterward (IE it never ran fallow, truly)
2) I cross-contaminated my tank with my arm, nets, drainage hoses, pumps, etc.
3) The therapeutic level of copper was not achieved for the full term (more common prior to the use of the hanna copper checker now that we have a reliable, easy to utilize way to measure copper)
4) I introduced coral or other things "wet" without them going fallow


It happens, I learned!