Is this a hydroid... The bad kind?

[Mike.P]

Hey all... I found two of these on the glass of my invert/coral QT last night. They're about the size of the tip of a pen, I'm actually surprised my phone got as good of a picture as it did. They seem to fluoresce green a bit too. Are they hydroids and, if so, are they the nasty kind? I've never dealt with them before, so I'm not sure what to do. Thanks!

 

[Crabs McJones]

Medusae hydroid
They tend to die out on their own as the tank matures

 

[Mike.P]

Medusae hydroid
They tend to die out on their own as the tank matures

That's great news... Thank you! ;Woot