little white starfish?

I know I didn't put these in my tank I also know they have benefits being in there but is there a point they get over populated??

 

They're asterina stars. And yes, they can reach a point of "over population". I'd start picking them out if I were you.

 

If your other tankmates will allow it, get a couple harlequin shrimp. When the asterinas are gone it will have to be fed but they are really cool shrimp. Here is a favorite pic of mine...

IMAG0293 - Copy by SaltyDawg_2009, on Flickr

 

If I have more than a dozen or so on my glass I just suck them out when I do my water changes

 

I have one. Lol