they hog drift wood

I had 7 neon tetras 2 mollies and 3 guppies now I have 7 neon tetras 2 mollies and 2 guppies I've heard they can be guppy eating brats are they achuly ghost shrimp I've had them for like 3-5 weeks so they aren't too big are they different shrimp all the fish/ghost shrimp are from pet smart are...