Strange Hydra-Like Organism On Glass

[Lowells Fish Lab]

Can anyone identify what these are? They behave like hydra but don't look like any freshwater species I have found online so far. I've eradicated them before with fenbendazole but just had some reappear in a recently set up tank.

[Maggie]

It's hard to tell from your pic. Up close do they look like this with a "forked" head? If so, then it's hydra. 

[shkote]

@Daniel has a lot of posts about vorticella that are worth searching. 

[gardenman]

It could be a slime mold. They eat the biofilm on glass and other surfaces then disappear.

[TheDukeAnumber1]

Hard to tell but looks similar to freshwater bryozoa.

 

 

[Lowells Fish Lab]

Thanks for your responses. I found similar photos / reports after searching for vorticella on aquarium glass. 

I found at least one discussion that suggested they are zoothamnium, a relative of vorticella. Sounds like they aren't a threat to fish or invertebrates.

Thanks think tank!

[jesso435]

OP did you ever figure out what this is and what to do about it (if anything)? I have it all over my tank, too. Looks exactly like yours. 

[Lowells Fish Lab]

On 12/13/2021 at 12:20 PM, jesso435 said:

OP did you ever figure out what this is and what to do about it (if anything)? I have it all over my tank, too. Looks exactly like yours. 

Hi, after research my best guess was zoothamnium, a relative of vorticella. They have seemed to be harmless and have gone away on their own. Many of my newly set up tanks have gone through a phase where they appear, boom in population and then disappear completely never to return. My conclusion is that they're nothing to worry about.

[jesso435]

Thank you!