Thanks Rosie, David and Anita!
First I am very glad that my attribution is confirmed -- when I spotted the fish in a charity shop I just knew it was better than the usual Murano fish I am used to see
As to the technique: I am open to correction; I don't have the Heiremans book, so I don't know if the "Graffito" shown there is the same pattern as in my fish and in the vases I linked to. David is right that googling isn't the best way to research a Murano term...
@ Anita: do use my pics in your Zoo -- I sent you a message