Some amphipods, like the ones pictured above, develop a taste for zoas/palys. I prefer to get rid of any amphipods that come in on zoas from the outset rather than risk having a problem with them later on.
Mark
I know I have tons of those Amphipods in my tank. You can really see them at lights out crawling everywhere. The only thing I have more of are probably my Zoas. They completly cover the overflow, part of the back wall, and several rocks and are still spreading. Infact, I really should thin them out.
I have a Mandrin that is two years old and I am hesitant to do anything with the many "bugs" that are in the tank as I am not sure which ones are his food source. Better safe than sorry though I agree.