Murano?water filled glass beads

Hi. My neighbour has an old necklace that she says has been in the family since the early 1900s. She showed it to me yesterday. It is made of a brass chain holding together five small, glass, water-filled globes each of which has a tiny glass fish in it. One of the globes has broken so the whole thing has been put away untouched for many years. As a consequence the globes that remain are in very good condition and can give no indication of age.
Does anyone have any experience of this product or sort of item?
I'll try to get a photo to post but it is a bit tricky at the moment

These are they. The globes appear to be sealed at each end with the fish and the water within! How do they do that?
Anyone seen glass ones of these before? Apparently plastic ones are extant but they are probably easier to make.
The owner was wondering if the broken one could be replaced.

Moved to ID my Glass.

Never seen anything like them. If they are joined with wire loops,
it may be easier to just take the broken one out of the chain.

I did suggest that and it seems like a sensible option considering the probable price of a replacement globe.
Interesting objects though...