Pennies, I heard some guy lost shrimps when his students dropped pennies in his tank. Hey if you don't want your shrimps i'll take em.
Yeah I thought about dropping a small copper pipe but not sure if that would permanently damage some of my fish. I need a 100% sure way that gets it done within a few minutes or hours.
Unfortunately I've made up my mind to just get rid of the shrimp instead of catching them. Much easier and less time consuming.