What the...??? Please tell me what these are.

Hi, The title says it all really. I have no idea what this is and am hoping someone can identify it/them. There are many of these things attached to the glass of my aquarium. To the eye, they look like little gray flecks partially stuck to the glass. So far, they are only in the area where the filter flows heaviest.

I just noticed them today so I did what any normal person would do and I scooped up one with a pipette and stuck it under the microscope. There is a sandy tube thing with many branches off of it. Each branch has many flower or bell-looking things that open and close. Within the sandy tube, there is a small oval that travels back and forth along the length of the tube. It appears to have appendages that make a grabbing motion at one end and then it travels down to the other end.

My filter broke last month so I set up another one that a friend gave me. It hadn't been used in a few years, so I'm not sure whether these mystery things come from the filter or not. There is nothing else new. No new food, no new critters, no new plants, nothing. Not sure if I should be alarmed or if this is yet another one of those things that will sort itself out.

Thanks in advance...

Sounds like you're describing hydra.
I loved having them when my tank started. They're super cool to watch. Closest thing to saltwater corals in the freshwater world. (I'm pretty sure hydra is actually in the same family as coral, but don't quote me on that)
They're relatively harmless, but if the fish is small enough (like the size of fish fry), the hydra might make them a meal lol.

I'm not sure about hydra. I looked those up and they appear different. Do my picture and gif come through? I see them on my end, but I don't know if others can see them.

BeckyCats said:

I'm not sure about hydra. I looked those up and they appear different. Do my picture and gif come through? I see them on my end, but I don't know if others can see them.

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Ohh, I thought you were saying you took a sample of whatever it was and put it under the microscope...
Yes, I can see those. I have no idea what those microscopic organisms are

Oh, I forgot to put one of the pictures up. This one shows the little bell-things better.

We just had a thread with the same sort of critter! You can find it here

The branched organism looks like some sort of colonial ciliate. I don't know of any ciliates that make tubes that get sand stuck to them, so I wonder if it's a small tube-building worm that the ciliates are growing on. I can't say with any sort of certainty without better photos or a video. Is your tank saltwater or freshwater?

Rocky998 said:

Ohh, I thought you were saying you took a sample of whatever it was and put it under the microscope...
Yes, I can see those. I have no idea what those microscopic organisms are

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Yes, these are the photos and video I took after I put the whatever-they-ares under the microscope. To the naked-eye, they are just little gray flecks, less than a millimeter long. Under the microscope, they look like pretty little flower-things. So odd!!

Seisage said:

We just had a thread with the same sort of critter! You can find it here

The branched organism looks like some sort of colonial ciliate. I don't know of any ciliates that make tubes that get sand stuck to them, so I wonder if it's a small tube-building worm that the ciliates are growing on. I can't say with any sort of certainty without better photos or a video. Is your tank saltwater or freshwater?

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I'll check out the other thread, thanks!

Freshwater tank. The substrate is sand, but these are all attached near the top. Of course, I imagine there are small particles of sand getting sucked up by the filter and these critters are taking the granules from the flow.

Closest I could find is genus Carchesium, a type of colonial ciliate. The link shows a image of an undescribed species. https://www.nature-microscope-photo...101f-carchesium-sp-protozoo-ciliato-125x.html

I'll try to get better photos tomorrow.

I wish I could get creatures like that in my aquarium. I had some hydras for a short time but they got consumed.