Help with my Ricordea.

[lxxnp1234]

I have it for about 3 months. Recently, it's not doing very well. Today I find there is a 'line worm' coming from its 'month'.
I don't know what is the 'line worm'. What should I do?
Thanks.

 

[lxxnp1234]

I compare the pictures in this website. I think mine looks like the green hairy mushroom coral.
Anyone can help me?

 

[cajonez]

Pictures are worth a thousand words...

 

[truperc]

Pic would be best. The so called "line worm" may be zooanthellae