Agreed. It feeds on phytoplankton.
I culture phyto and usually store the extra in fridge. Somehow I didn't know that some of the BS got mixed into the phyto. So one day I took out the bottle of phyto, which is sealed tight, and I saw adult BS swimming in it. It's somehow black in body, unlike those bought in LFs which is pinkish. I heard those feed on chicken shit. So don't simply pour the water into ur tank.
I watched some documentary that BS actually found in sea, not so sure about blackish water.