Help identifying this please!

[serecheneric]

Hello can someone please help identify what these are please. They range from incredibly small upwards of maybe half of an inch, small white and cylindrical in shape. They don't seem to attach to anything and when blown with turkey baster they float around for a while before settling on top of wherever they land. I haven't noticed a head or tail or anything resembling one. Nothing coming out of the tubes upon expecting them. I have no clue where they came from but seem to have multiplied somehow upwards numbers of 50 or so. I managed to snag one with some long tweesers and it felt quite soft compared to what I originally thought it would, reminds me of a small feather duster shoot which in my experience are much harder. They don't seem to be free moving either unless I'm missing something lol.
Mainly wondering if they are harmless, and if not then what the best course of action should be.
Any and all help is greatly appreciated!

 

[blaxsun]

No idea...

 

[Cell]

Probably fish poop.

 

[serecheneric]

Awesome, thank you guys. Just didn't figure there would be that much with 3 small fish and continuous high flow environment.