just been watching my pregnant guppy is it noraml for her to attcack the the males and other females it look like a small tube hanging from the back by her gravid spot
Yup, I reckon she's about to drop. She's being anti-social, she doesn't want other fish near her when she gives birth.
The tube is the birthing tube, its open so she's about to drop her fry.
as the others have said - it's perfectly normal. Guppies tend to become defensive when they're ready to drop. My female guppy is the only fish that likes being trapped - she'll actually swim into the net and go in happily. It's almost like she's happy to be alone and left in peace for a bit