Looking for info on a sea mouse

[FishInABarrel]

Does anyone have any info on these? Water parameters, care, feeding, etc. I was looking for sand dollars and someone said they had sea mouse and heart urchin. They said they were similar but I haven't found much on sea mice.

 

[neontreefrog5]

its a type of polychaete worm. heres more info:

http://www.marinespecies.org/aphia.php?p=taxdetails&id=129840
http://eol.org/pages/464120/overview