I'm looking for a good sand sifter, but also want something that won't eat copepods, or at least wipe out a possible copepod population... In a few months I'm looking to get a Green Mandarin, so I'm working on a copepod population for my 44gal tank.
While at one of my LFS's, I noticed they had about 10 horseshoe crabs running around a tank, each being about 1 1/2 inches long, and was interested in getting one, so I decided to research. To my delight, I found LiveAquaria states "When small, they are very efficient scavengers and are great for aerating and maintaining sand beds.", they are reef safe, easy to care for, and minimum stated size tank is 30gal.
Then I thought: "If he aerates my sand, he might eat all copepods that might be living in there", which is the reason I haven't bought any orange-spotted-gobies.
Although, could I, instead, seed the refugium with a Reef Pod or two to grow the copepod population, and still go with the horseshoe crab? (I'll have to return my pinfish to the lagoon though, as he might eat the copepods)