# Do I have magical isopods?



## irish_creep (Sep 9, 2014)

Sorry for my ignorance, but I know very little about the terrestrial flora and fauna of vivariums.

I was doing a “dry start” to my planted aquarium, which basically means that I was growing certain plants in emersed form before flooding the tank. I put 2 isopods (that my kids found at the park) in the tank during this process to try to reduce mold, as the method requires high humidity.

2 days ago, I flooded the tank, taking care to stop at a certain point to rescue the 2 isopods before fully flooding.

Nearly 24 hours later, I noticed some white things on my moss, which looked like huge scuds, but actually turned out to be tiny isopods (I’m assuming they are the offspring of the 2 that were in there).






I tried to take out as many as I could, but way easier said than done.

Today, nearly 48 hours later, I still see them, walking around and munching on things as if they weren’t underwater.











Everything I’ve read said that “roly polys” can’t live underwater. Or is this a myth?

Also, not sure if relevant, but there is no CO2 or airstone running in this tank yet, just an HOB filter with filter floss.


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## Socratic Monologue (Apr 7, 2018)

Looks like the critters in your tank are white. Did your kids find white isopods?


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## irish_creep (Sep 9, 2014)

Socratic Monologue said:


> Looks like the critters in your tank are white. Did your kids find white isopods?


One was, I would say, a “light black”, and the other was more of just a straight grey.


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## irish_creep (Sep 9, 2014)

Sorry, not the greatest pics, but just took these now of the “parents”.


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## Socratic Monologue (Apr 7, 2018)

What genus are those parents, @fishingguy12345 ? They don't look like the native isopods here in Wisconsin.

There are aquatic isopods in the US, it seems:














Aquatic Pillbugs and Sowbugs (Aquatic Isopods)


Everyone knows about terrestrial sowbugs and pillbugs, but many isopod species are aquatic. Missouri has several isopods that live in streams, ponds, rivers, and caves. Isopods are usually dark brown or gray, flattened top-to-bottom, many-segmented, with head, thorax, and abdomen not immediately...




nature.mdc.mo.gov





Any chance there were some materials from wild waterways introduced into the tank?


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## Louis (Apr 23, 2014)

These obviously really are baby isopods, I think they're able to survive because of how small they are and how little oxygen they need. Because they are so closely related to shrimps their breathing system is still able to extract some oxygen from the water I reckon.


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## irish_creep (Sep 9, 2014)

Socratic Monologue said:


> What genus are those parents, @fishingguy12345 ? They don't look like the native isopods here in Wisconsin.
> 
> There are aquatic isopods in the US, it seems:
> 
> ...


Very cool video. I don’t think there’s much chance that they were accidentally introduced, as all the plants that I used were tissue cultured (except for the moss, which has been in a grow out tank for the last month). And I had been letting the branch leach out in a tank with chlorinated water for the last month as well.

The only “wild” thing that is in my tank is some organic potting soil that I spent a couple weeks mineralizing. I don’t know- there might have been a random isopod in that?


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## irish_creep (Sep 9, 2014)

Louis said:


> These obviously really are baby isopods, I think they're able to survive because of how small they are and how little oxygen they need. Because they are so closely related to shrimps their breathing system is still able to extract some oxygen from the water I reckon.


Yeah, that was my original line of thinking as well, but my quick attempts at learning anything through a search engine was sort of a failure because every time I’d type in keywords, tons of articles about big oceanic isopods would flood the search.


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## Socratic Monologue (Apr 7, 2018)

I just submerged about ten dwarf white isopods, and once they broke the surface tension, they crawled around just like the ones in your video. 

The only relevant study I could find in a quick search:









(PDF) Terrestrial life in isopods: evolutionary loss of gas-exchange and survival capability in water


PDF | Survival and oxygen uptake in air and water were investigated in four species of terrestrial isopods, Armadillidium vulgare Latreille, 1804,... | Find, read and cite all the research you need on ResearchGate




www.researchgate.net





Interesting stuff.


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## fishingguy12345 (Apr 7, 2019)

They look like Armadillidium vulgare to me, which would make sense with the location on the poster.


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## Louis (Apr 23, 2014)

Socratic Monologue said:


> I just submerged about ten dwarf white isopods, and once they broke the surface tension, they crawled around just like the ones in your video.
> 
> The only relevant study I could find in a quick search:
> 
> ...


I have a vivarium with a water feature and when I drain it to do a full water change huge numbers of Trichoniscus pusillus isopods migrate to areas that were previously submerged to feed on the algae and other biofilm. When I fill it back up they mostly rush to avoid the rising tide BUT the ones that get caught out and submerged don't seem to mind and just slowly make their way back to the surface grazing along the way. It seems they instinctively avoid the waterline but aren't actually particularly affected by being submerged.
This makes sense if you think about torrential or sudden rains penetrating soil. They'd need to know that it was a cue to move upwards but also be able to survive long enough submerged to actually make it to the surface if they aren't able to avoid the rising water table which I imagine would be quite often.


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## Kmc (Jul 26, 2019)

Excellent insight.


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