All small fish and shrimps will be killed or eaten by Bettas.
Bettas are aggressive fish and its their natural instinct to fight or even to kill.
Probably only the veil tail Betta is ok in community tank with peaceful but bigger fish. But its big tail will be at risk.
Other fish will nip its big tail and fins.
I think you just put it in a container as someone suggested earlier with an air stone.
Get the biggest container that you can.
Very importantly, acclimatize the shrimp slowly with the water in your container.
Recently, I watched a youtube video about shrimps.
The person has two tiers stand for tanks.
The top tier has mostly aggressive fish plus Peacock Gudgeons.
The bottom tier has all his shrimps.
One day, one of the Peacock Gudgeons accidentally jumped out of his top tank and landed in the bottom tank.
He said his whole colony of shrimps were wiped out/eaten by the Peacock Gudgeons.
That is how aggressive the Peacock Gudgeon.
