What are these critters ?? Bad/Good

[cyberbug]

I bought some rock and put it a holding tank untill my 210 is all set up. There are very few corals in it. But I have these little red things. They look like little slugs everywhere. It's to the point that I'm getting worried for the tulip.... They are on the rock & the glass just everywhere. I don't want to mix it with my other rock if it's bad
Thanks,
Angela

 

[salty cheese]

Do they look like the pic below? If they do, then they are red flatworms and can become a problem if their population becomes too great.

 

[cyberbug]

Yep, That's them alright... They are everywhere in one of the tanks. The others I haven't seen any... How do I get rid of them?

I don't want them to make it to the 210.