I had some lampwork glass fish that floated suspended from finely blown glass balls in the early '70s, but there was no metal chain, like this one, there was a glass hook on the float ball.
A few of them came to a sticky end in a fight with a light bulb in pot of hazlenut yoghurt, (I did say it was during the early '70s!) but I replaced them not too many years later when I found more. (I just dug them all out again recently!)
The fish are very similar. But I would suspect the metal chain may well indicate that yours predate the ones I have.
I did buy them singly, and had to provide my own bowl.
