[flamingo]

All you can do is possibly have a smaller predator such as arrow crabs, etc. if your tank can afford it, and manually remove them. I wouldn't solely count anything as a surefire way to rid your tank of them. Just make sure not to harm any while they're in the tank- as they can spread easily when stressed.

They aren't predatory, but an infestation can harm fish if they come in contact. On a few occasions, my seahorse went after a few- thankfully never snicking at it.