Okay, after the bettas figured out that the red dwarf shrimp were actually an expensive appetizer (well, they kinda are), I decided I needed a place for the shrimp to hide, so I constructed a shelter for them to evacuate to.
It uses the same needlepoint plastic canvas as the dividers with the pieces smoothed and attached using an aquarium compatible silicone.
(Insert photo of it installed)
I just hope they don’t stay in there all the time. Time, and hopefully the population, will tell.