Don't know what this is.

[ThatGuy]

Its hard and branches out. Its growing on the underside of my bubble coral. Any info would be great.
They're the red things.

 

[absoluteshawn]

Is it a sponge? I have that growing under my bubble coral as well as a favia. One I have is blue, the other is reddish like that.

 

[ds4x4]

looks like a sponge to me

 

[ThatGuy]

Its not soft at all. Is there hard sponges?

 

[Jcurry@wesketch]

They're Cnidaria, commonly called fire coral although they're not really a coral. They're common on freshly imported live rock but rarely get bigger than 1/4 to 1/2" in the aquarium. they'll eventually die off.

 

[ThatGuy]

They're Cnidaria, commonly called fire coral although they're not really a coral. They're common on freshly imported live rock but rarely get bigger than 1/4 to 1/2" in the aquarium. they'll eventually die off.

Had them for about 3 months and if anything they're spreading. Also when I try to look up CNIDARIA it pretty much say's any marine animal that has specialized cells to capture prey.
http://en.wikipedia.org/wiki/Cnidaria

 

[redfishbluefish]

Cnideria is the phylum that fire coral fall into. It would be like saying we (man....Homo sapiens) are chordata. If you search chordata, you will get every animal that has a spine. You would be better off searching fire coral.

 

[ThatGuy]

Don't think its a fire coral. Is more of a yellow than red and gets its name from its sting rather than appearance.

 

[ThatGuy]

Figured it out. Its a form of Homotrema rubrum. Can't find much info but its been there a while so I guess its okay.