there is 1 simple and easy way to prevent the food from being eaten by other fish...
Cut the top part of a 1.5L bottles, cover ur sun coral with it then use a tong to place the food in this works for prata too.
most of the corals we got comes with base rock so we just place it on our LR. if in the event that the coral drop off from their base rock we can use super glue(gel type), if u are afraid on toxin etc u can use eproxy.
erm.. the stocks there r expensive compare to those in hdb.. if fact i dun really like to shop at there the marine shop does not accept nets.. last time only waikai is the only marine shop that accept nets but it has close for good le..