What are these please help

[chubbyhubby]

Hi was look at tank and this work type thing come out back and white on top but plane white on bottom with a feather duster type head that went in and out . Plausible some thing growing around back of rock tryed to get a good pic .

 

[kashman100]

1st and 2nd picture looks like peanut worm

 

[chubbyhubby]

Are they are good or bad thing for my tank

 

[KJ]

3 picture Aiptasia .

 

[KJ]

Are they are good or bad thing for my tank

Yes the are good for you tank

 

[chubbyhubby]

What are aiptasia and are all 3 pics good for tank

 

[KJ]

What are aiptasia

http://reefkeeping.com/issues/2004-01/ac/feature/index.php

 

[chubbyhubby]

Ok thank you for your help seems they can be a pain