All is not so bleak. The decanter is a Bischoff Brandy decanter. Glass and ceramic artisans from various places made collectible decanters for Bischoff Brandy. Murano glassmakers made many designs, including the one in your picture, during the 1950s. Your decanter is often attributed to Fratelli Toso, but there is no evidence they made the decanter. I have had a couple of these decanters and the clear glass is too crystal-clear for Toso, IMO.
Other Bischoff Brandy decanters made in Murano include the ones with lion-head's prunts set like a doughnut hole in the middle of the decanter. These are often attributed to Salviati, but the attribution is doubtful. I believe the most we can say about these decanters is that they were made in Murano for Bischoff Brandy (which is Italian, I believe). Bischoff Brandy is a liquor company with no ties to Bischoff Glass that I know of.
(I just noticed the advertisement in the listing has pictures of the decanter I was writing about. The advertisement is a great help for people who run across these decanters often. I did not know what they were until I saw this advertisement the first time.)
Anita