hydroids

Can anyone help identify this thing that showed up today in my tank? I think it’s hydroids but have no idea if it’s good bad or something neutral. Any help would be awesome! I have attached a photo taken today Thanks!

How harmful are they? How badly do they sting. If so, do they sting humans? If removal is needed, what should I do? If removal is not needed. They're pretty dang cool

I have some colonial hydroids and they’re spreading fast. What’s the best way to get rid of these?

In the past month, I’ve been noticing more (what I think is hydroids) cropping up on my rock. Can anyone confirm? Also, noticed some tiny white specks on my glass, but it was hard to get a good picture. Literally look like tiny grains of sand on the glass. No distinguishing features that I...

So I have this stuff that has pretty much taken over my tank and I can't get rid of it. I'm looking for an ID and an eradication plan that is anything short of a total teardown.

I've got a Fluval edge 6g nano that's been up and running about 5 weeks now. No fish, just CUC and random hitchhikers. I noticed the first couple of d.hydroids a couple weeks ago isolated to one rock. They have since spread to most of the other rocks. Not infestation levels yet, but a good 6-7...