Betta will eat baby shrimp for sure, without a doubt. They will also "nip" at any dwarf shrimp(cherry, crystal red etc). Just because a shrimp can't fit in it's mouth doesn't mean they can't kill it by pecking at it. So should you get some shrimp? Yes! You may want to try Amano or ghost shrimp as they are bigger and the Betta will leave them alone. You can have the dwarf shrimp too but you have to be okay with the occasional dead shrimp and little to no babies. My 30 gallons has like 200 dwarf shrimp so I really don't have to worry about my rams and honey gourami eating them all but they do get some of them.
