Also just because the betta couldn't catch them, didn't mean it didn't harass them to death. Some betta's are relentless, especially after the lights go out. I've had fish with a betta, seemed fine, lights go out, dead fish in the morning.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.
Sump Pimp #2
My Tanks and my shrimps