Amphipods & copepods, they will just grow and multiply naturally in your tank as it matures. It would help if you will dose phytoplankton as it is one of their good food source.
Personally, I made a pod condominium .
Made out of rubbles and crush corals wrap inside a net. dun sila dumadami ang once in a while nililipat ko sa main DT para pagpyestahan ng spotted mandarin ko (c/o Bro Trowa).
Siguro magiging issue mo na lang sa pagpapadami nyan is if you introduce other LS that will out compete with your mandarins sa pagkain ng pods like wrasses and anthias.