What is the difference between a lamprey and a hag-fish?

a Hangfish has:

a single nostril at the tip of its snout

and has sensory tentacles around its mouth

as well as slime glands and 1 pair of gill openings.

A Lamprey has :

a mouth lined with teeth

a single nostril at the top if his head

7 pairs of gill openings

and no slime glands