I added a Porcupine Puffer to my aggresive tank 1 week ago. I can't get him to eat frozen food at all. I have tried squid, krill and silversides. When I added two live minows he ate them. I heard feeding freshwater to saltwater is unhealthy, but even using tongs tomake the siversides look alive, no luck. Is it bad to feed him live food? If so any suggestions? He is starting to eye the other fish as food.