badminton birds in my tank on glass?

These things are on the glass (looks like a spider) when swimming it looks like a badminton bird? I would like to know what these are. They started attacking my baby seahorses

 

pictures?

 

I will try to send pics

 

I cant get the pictures , I have no idea about finding it url

 

Do you know if these are trying to kill my seahorse babys? The land on them and pin them to the bottom or to the glass

 

if they are hydroids like what mission brought up (look at his pic from google), then they are not attacking your seahorse. They harmless, and when knocked off of the glass, will land on whatever they stick to. Including your seahorses and my six line wrasse.

That's my view of them, if there's something I'm missing someone chime in. But that's what's goin on with my setup. My 6 line gets them off of him pretty quick, the cleaner shrimp helps though. His constant desire to touch my fish knocks off the little things pretty easily