irenedeserti's Identifications

Video link: https://youtube.com/shorts/Jb2eq_JayVs?si=3E_z6Yag5a_rm3o7

Growing on sponge filter in minnow and snail tank
Still when first observed. I moved a plant and stirred up some mulm. Here, they are consuming the mulm from the water column.

These appear white, unlike the vibrant green of some hydra. I'm not sure if these actually are white/clear or if the lighting at the back of the tank alters their appearance on camera. The transparent body of hydra might show what they are eating.
Edit: turns out some species contain symbiotic strains of algae, which makes them green, although they don't consume it.