Unknown red threads on liverock

[raseshJ]

Hello all,
Am new to reef aquarium from India.
My tank is been running for past 1year.
Few days ago I noticed red threads on live rock. Please help if this is good or bad for the aquarium.

Salinity 1.027
Temp 26°C
Ph 8.3-8.4
dKH 8
Nitrate phosphate negligible

Dosing calcium magnesium kalkwasser
Aquaforest amino
Phytoplankton


I have attached photo for reference.

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

This is probably a Spaghetti Worm (taxonomic family Terebellidae) - they're harmless/beneficial.