Not sure if this is fine?

[ferdieck890]

I just started 2 months ago with this new tank, and when I checked my tank this morning I saw these lines, which I thought were cracks but they have like dots with super tiny tentacles or polyps on them. I bought a blasto and a torch that died 3 weeks ago, but the blasto is doing good. I'm not sure if its a hitchhiker and should I be worried about it? What should I do?

 

[mypocketreef]

Looks like some type of bryozoan! Personally would remove if possible, I don’t think it’s an immediate threat unless it’s growing/ interfering with corals!

 

[ISpeakForTheSeas]

I just started 2 months ago with this new tank, and when I checked my tank this morning I saw these lines, which I thought were cracks but they have like dots with super tiny tentacles or polyps on them. I bought a blasto and a torch that died 3 weeks ago, but the blasto is doing good. I'm not sure if its a hitchhiker and should I be worried about it? What should I do?

Welcome to Reef2Reef and apologies for my slow answer here!

It is a hitchhiker - you have some hydroid (Hydrozoan) polyps there; I can't say for sure what species from the pics (I would need very close-up, clear pics of the polyps/tentacles themselves), but it looks remarkably similar to a species commonly found in our tanks called Cladonema radiatum. These have a polyp life stage and a medusa life stage (the medusa looks like a tiny jellyfish).

For reference/comparison:
Polyps (posts 1 & 8; post 10 has some medusa pics, but they're not super clear):
https://www.reef2reef.com/threads/roots-on-glass.1063454/Medusa (post 7):
https://www.reef2reef.com/threads/coral-shrimp-larvae.1035909/Edit: To add, Cladonema hydroids usually go away on their own after a while (once they run out of foods).