I have a 'goldfish bowl' vase with the same fishy decoration. It is about 7 inches in diameter , and the body is of smoky brown glass. The 3 fish that circle the bowl among fronds of weed are blowing bubbles. The fish and weed have silver overlay, but the bubbles are just transparent areas. The background is heavily stippled.
Absolutely no idea who made it, but it appears mass-produced, and I had always assumed that it was post-1930.
It is a nightmare to photograph to try and give any kind of realistic representation.
Fred.