Anyone Know What these Are

[King of the Sea]

Got them growing all over just wondering what there called

[HiddenReef]

hydroids, bad news.

[King of the Sea]

:sad: Why

[Der_Iron_Chef]

Cause they can sting the @#%& out of your other corals if they come into contact!

[Joe Reefer]

Take a look here (http://www.xtalworld.com/Aquarium/hitchfaq.htm), from what I hear they are a PITA to get get of.

[Ruth]

Hydroids are bad if you have any type of coral. They multiply and spread very quickly and will sting and kill coral. If you have a fish only system they are not harmful.
They are very hardy and can be just about impossible to get rid of. I have even heard of people taking a blow torch to their rock trying to get rid of then (not recommended).

[Delphinus]

They can spread indiscriminately through the tank and they burrow into the rock so simply scraping them off doesn't get rid of them (they just grow new heads). Corals tend to do poorly if these are with them in the tank.

[christyf5]

Get out a hammer and chisel, its the only thing I've had any success with. I am running an epoxy experiment right now (epoxied over a whole batch) but I can see a couple sticking out at the edges of the epoxy so not a grand success :neutral:

[King of the Sea]

Does anyone know exactly how close they have to be to sting?

[Oscar]

Got them growing all over just wondering what there called

Did they arrive with your live rock?

[Der_Iron_Chef]

Anthony Calfo's response to a hydroid question on WetWebMedia:

"Your real solution is to get to the root of the problem (excess nutrients) and not focus on the symptom (hydroids flaring). Focus on starving them into submission and then polishing them off with a lite bit of manual control. Improve water changes, be more aggressive about skimming, increase water flow to get excess food/particulates exported rather than lingering to feed the hydroids, etc."

[Snappy]

Anthony Calfo's response to a hydroid question on WetWebMedia:

"Your real solution is to get to the root of the problem (excess nutrients) and not focus on the symptom (hydroids flaring). Focus on starving them into submission and then polishing them off with a lite bit of manual control. Improve water changes, be more aggressive about skimming, increase water flow to get excess food/particulates exported rather than lingering to feed the hydroids, etc."
I second that :idea:

[KrazyKuch]

If their isn't any corals on the rock I would just boil it....doesn't seem to be that big of a rock!!