What is the best glue for glass

The backstory: My mum has a vintage depression glass float bowl (like this one http://shamrockgardenantiques.com/images/FishCenter.jpg) but the fish has broken off. Mum would like to repair it and she was told to use a single tube glass repair glue that is set by uv light and has the same refractive index as glass - I’m having trouble finding anything suitable (and available here in Australia)
Any help will be appreciated.

I guess I’ll be the first: www.thistothat.com

Contact the nearest place that does auto glass repair work. The glue that they use to fix cracks and chips in windshields is also UV activated and probably what you need. They will have the UV curing light and might fix the bowl for a small fee, probably cheaper than your buying the glue and light.

Info for all your adhesive inquiries: www.ThisToThat.com!

Possibly easier and cheaper to find would be rear-view mirror adhesive. AFAIK, it’s the same stuff as the chip repair kits, but without the suction cups, syringes and whatnots.

Provided no other repair attempts have been made, you should be able to put a drop or two of the mirror adhesive on the bowl, put the fish back on, then set it out in bright sunlight for a few hours. You’ll need to support the fish if it doesn’t stay put on its own - this adhesive is not terribly sticky in its liquid form.