Should i worry about these guys?!?

[FloatinBy]

What the heck are the tiny white things with the arms? Are they good or bad? Thanks for the help in advance.

 

[KJ]

Hydroids watch them. Diet: Small plankton and particulate matter. Not a problem except in breeding tanks.

 

[FloatinBy]

There are a boat load of them on my glass all of a sudden. And i mean a boat load.

 

[FloatinBy]

Nah mostly gonna be fish amd corals. Whyd the population just exploid? Ive mever seen them before

 

[Lovemyreef2015]

How old is your tank? When we set up our mother-in-laws nano, within a few weeks they showed up. It got worse before it got better. After a few months they just went away on thier own.

 

[FloatinBy]

The tank is like 7yrs old but ive had it for only 4months or so