What are these on my rock

[Albz]

Soo these white tubs growing in my sump on the rock.. it does have feather dusters on the tip... soo can someone confirm if they good or bad lol

 

[Flippers4pups]

Feather duster worms. What specific species? Don't know. They are completely harmless. They typically live and grow in lower light environments. Will self regulate depending on available food.

 

[Albz]

Feather duster worms. What specific species? Don't know. They are completely harmless. They typically live and grow in lower light environments. Will self regulate depending on available food.

Thank you for the help@