ID string algae that shrinks

[TheCatsCoral]

This string algae is starting to take over the tops of the live rock in New tank (3months). Trying to remove with tweezers does not work as they shrivel when touched so they grow back. Corals and clean up crew are happy CUC won't eat this algae, only have one astrea which cleans the live rock, the other snails stick to the glass and sand even though these other surfaces are clean

Nitrates remain at 0. Phosphates around 0.04ppm.

3x Ceriths
1x Banded trochus (recently had babies in tank)
1x nerite
1x astrea

Thanks!

 

[vetteguy53081]

Looks like hair algae but if it shrinks, may be feeders from spinoid or vermetid snail

 

[Gtinnel]

Do they have little ball looking things on the ends? If so I'd guess digtate hydroids.

Edit- After looking closer I'm less confident on my answer. Either way if they move it isn't algea.