wierd slugs in my zoos. HELP

[andsoitgoes]

I bought a zoo rock from hidden reef a month ago, and within a few days from going in the tank, the zoos snapped shut. Couldn't figure out why until, about 3 days later, I saw what looked like a nudibranch climbing across the front glass.

Took the little sob out, lo and behold the next day my zoos were out saying hi.

I got lucky, dip that sob asap before you're sol!

Ok???