Can ich lie dormant?

[SalviniCichlidFan]

I was reading through various forums and heard that ich parasites can lie dormant in the substrate for long periods of time (even without fish present in the tank) until a stressed fish is introduced into the tank, where the dormant ich parasite begins to infect it.

Is this true?

It doesn't make sense to me because parasites should need fish/hosts to survive.

 

[Deadeye]

The ich life cycle involves an encysted phase where it rests on surfaces. These then hatch into more pats stores, which infect the fish. I don’t know the exact length for freshwater ich (Ichthyophthirius multifiliis), but for marine ich (Cryptocaryon irritans) it can last up to 60 days without a host.

 

[Hybridfish7]

I was reading through various forums and heard that ich parasites can lie dormant in the substrate for long periods of time (even without fish present in the tank) until a stressed fish is introduced into the tank, where the dormant ich parasite begins to infect it.

Is this true?

It doesn't make sense to me because parasites should need fish/hosts to survive.

Iirc the ich dormant period is only like a week or two. Certain strains can even live out of water for a period of time. Also ich is a fungus.

Most parasites have dormant "cyst" stages that can be very long lived. Namely cryptosporidium.

 

[duanes]

Although most ick are timed to hatch quickly, there are always a few individuals that are programmed to stay inert for long periods, perhaps an entire season.
Consider desert pools that dry up, yet some ick are found to infect a year later.
Consider pools that freeze solid completely every winter, yet Ick appears every spring.
These are survival strategies that have helped ick survive tens of thousands of years.

 

[SalviniCichlidFan]

Thanks for the info everyone! I was asking this because I'm going to start a research project on ich dormancy which I'm really excited about

 

[duanes]

This should;d be an exciting project,
Great as a PHD thesis.
it will be interesting to see the results.
Out of every hundred ick parasites how many are programmed to go innert,? Will it be 1 out of 100?,....1 out of 1,000?, 1or out of 10,000?
And how will you determine the method of counting? and separation?
As a former bucket microbiologist, this sounds daunting.
Not easy, like growing colonies of bacteria in a petri dish and counting colonies grown in an incubator.

 

[duanes]

Where I worked, we strove for accurate cryptosporidium counts in great lakes water, and the resulting treated water.
Each day we put a few thousand liters or raw water thru 0.05 micron filter, and counted oocysts, and the equal amount of finished water as well..
We also had "on-line" particle counters that measured and counted anything in that particular size range.
I would imagine trying to find and count those few inert ick cysts out of thousands would be much more difficult, just because of the time element.

 

[jjohnwm]

Also ich is a fungus.

Absolutely not a fungus, it's a parasitic multicellular organism, Ichthyophthirius multifiliis.

The idea that Ich lies dormant in tanks has been "common wisdom" forever, at least as long as I have been keeping fish. It's hard to argue against that idea, given the way that Ich can suddenly appear in tanks that haven't had any new fish introductions for a long time, but still develop an Ich infestation when the fish are somehow stressed, usually by chilling. Nevertheless, many aquarists didn't believe it.

It would be wonderful to read a new study on the current "actual" wisdom regarding this unpleasant little critter.

 

[esoxlucius]

given the way that Ich can suddenly appear in tanks that haven't had any new fish introductions for a long time,

This used to be a real mystery to me back in the day. How the hell can your fish get ich when no new fish have been added, and ich isn't even in your tank? How? And then I began to realise that ich, like the airborne common cold virus, is possibly there all the time!! It's just waiting for a host to let it's guard down due to stress or something and then it pounces. That's the only thing I can think of. How much truth's in that I don't know.

I suppose also very similar to the bacteria which are responsible for the nitrogen cycle whilst setting up a new tank. One minute they're not there, and then, when conditions are favourable, they appear by magic without even adding any said bacteria to your tank!

One thing I take away from such goings on is that the microbiological world works in mysterious ways, lol.

 

[Hybridfish7]

Absolutely not a fungus, it's a parasitic multicellular organism, Ichthyophthirius multifiliis.

You sure? I've always been told it was a fungus, and I've always treated with antifungals. If so I've been lied to, and I have shamefully made the mistake of telling people the same.