Found two critters on one polyp

[ledger]

Found these two creatures on this polyp while looking closely, one is darker and on the other is like a tiny almost translucent worm with a dark line on head, anyone able to ID/ give best course of action needed?

 

[KJ]

Look like Isopod serolid.

 

[ledger]

Look like Isopod serolid.

Thanks, are they harmful? Also know anything about that clear worm thing on its right side (So stalk as the isopod) just appears to be moving back and forth on it

 

[ledger]

Here's another picture of the worm

 

[KJ]

Here's another picture of the worm

Google Peanut Worm

 

[KJ]

are they harmful?

Yes algae grazer.