Whats this?

[what_isTHIS]

hey so I just got this aquarium 2 weeks ago and noticed this weird stuff growing all around my rock, anyone know what they are? Picture isn't the best sorry bout that

 

[blaxsun]

Could you circle the weird stuff?

 

[ISpeakForTheSeas]

Looks like it may be colonial hydroids - it’s generally recommended to remove them.