Just make sure the ones you feed to your fish do not have horsehair worms in them. I can't remember any possible impact on the fish's health when fed with horsehair worm-infected ghost shrimps but it's always better to err on the side of caution and destroy the entire shrimp stock if infested with that worm. Very easy to figure that out since ghost shrimps are transparent and the worm can be seen squirming inside.