'Hang' & 'deposit back upon'

I found an expression in Lamb's Dream Children where he busies himself with watching the sulky pike hanging midway down the water in silent state, as if mocking the playful movements of other fishes. Does 'hang' mean here 'to stay still without movement'?

And also,

John deposited back upon the plate of grapes as he heard that his father ( Lamb) never had touched fruits when he was a child.

Does 'deposit back upon...' mean lean back upon/ over the plate..'?