Underwater millipede??

[Emma]

I found what I’m pretty darn sure is a millipede in my tank. Is this a thing? Should I be concerned?? 🤔

It’s roughly an inch long and it’s hard to see but it does appear to have two pairs of legs per segment so I’m fairly certain it’s a millipede. 

[GardenStateGoldfish]

Never heard of such a thing but this is certainly interesting, can you tell what it eats yet? 

[Guppysnail]

I had one (that looked very like yours but who knows) when I was much younger and collected stuff from the creek. It was pre computers so I never knew what it was. I just googled and found a name but not a whole lot of info (I didn’t look to hard though I was just curious. @Biotope Biologist would know.  Possibly uroblaniulus carolinensis.  

[Biotope Biologist]

I think you are correct that it is a juvenile uroblaniulus carolinensis. While they can survive underwater they are not a true aquatic invertebrate. If it's native to your area I'd just return it to a nice pile of leaf litter.

[Emma]

Thank you, everyone! I'm in California. Since I have no idea how it even got in my tank, I euthanized. If it is uroblaniulus carolinensis I don't think they're found around here, or at least a quick google didn't confirm those are in my area. It was hanging out on my marimo, and certainly quite a surprise.

I have put some aspen cones in my tank recently, maybe that's where it came from. But I did boil them first!