I put three ghost shrimp in with my betta fish, Jasper. They were in a ten gallon tank with plenty of hiding places and I figured they would be safe because they are way faster than betta fish. They lasted about two weeks. Then I found just a head. Then a couple of days later, another head. And lastly, a half-eaten body. So, if you do decide to put shrimp in with your betta fish, be prepared to possibly lose them. They seem to be particularly vulnerable when they molt.