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I added a bunch of algae from the small yard pond to a "Muckquarium" (a pond life aquarium that I keep) a couple weeks ago, and stirred it up a bit and moved some of it around last night, but this is the first time I've seen this. 🤯

I have no idea what it is yet, though it has six legs, so I'm assuming it is some kind of insect larva.

It is alive. I gave it a very gentle touch with a stick, and it twitched slightly, took a short video, where you can see that it's abdomen/tail seems to be pumping slightly. I'm guessing that it is pumping water through as it breathes.

Any ideas? Perhaps a dragonfly larva/nymph? 🤔

Update: It swims, and is quite quick. Quick enough that I was having trouble trying to get video of it with my phone.