Ordered a new tank!

A very valid (here) fact is that Shrimps are invertebrates and as such have their 'skeletons' on the outside.
Great for protection - yes, but all shrimps have to replenish these exoskeletons periodically. A new one grows underneath the existing one and the old one then is discarded (hence why some newcomers think their shrimps have died, when in fact what they're seeing is the complete discarded old shell). It is when they have these new shells that all are most vulnerable. It takes a little while for the new shell to harden and makes them prey to just about any predator during this period. It matters not that they may be too large to be eaten whole, they just get broken into smaller bite-sized pieces.

However, there is hope here, I have five Amano Shrimps in a tank of breeding Bettas and they've been there - unassailed - for well over two years.
The female is often seen carrying eggs, but Amanos have a breeding process which makes it almost impossible for them to be successfully bred in our tanks.
When the young are released in the wild they immediately migrate to the sea, where they spend their early life - until maturity, at which point they return to fresh water to live and reproduce.
They are appreciably larger than many of our regular freshwater shrimps and - coincidentally - pretty good at eating unwanted thread algae. They seem to be very good at keeping away from my Bettas while in the 'soft-shell' state too. The only downside to them is they aren't the cheapest of shrimps, but, if my experience is anything to go by, are pretty long-lived. And, can periodically provide the fish with a gift of newly-hatched shrimplets.

So, for what it's worth, these would be my recommended shrimps.

John

When speaking to Darren on the subject he explained that it's a very 'hit-or-miss' affair.

Seemingly the trick is to have a salt water tank set up and move the embryos into it but...
too soon - they all die
too late - they all die

It really appears to be a critical timing issue.

I decided it wasn't worth the effort myself.

There are reports of people being successful if you check on goggle, but even then I don't think they have a 100% result.

Thinking about it, our native shrimps and prawns (and crabs) follow a similar pattern.