that rock looks like it has some good stuff on it
just as it should the snails are common on some liverock
and the green branch is a tipe of macro alga it can be a large pest in your tank once you have it you cant get rid of it that is unless you have a tang!!
my foxface seems to like it but it grows at an estomishing rate!!
you'll see
every peice that breaks off will grow!!
have fun weeding
cheers