I recently have purchased a Porcupine Puffer that seems to not be eating. All of the other fish in my tank eat frozen brine shrimp, which they enjoy so much (obviously over flakes), that they swim to the top and instantly gulp it down. The puffer, however, doesn't even eat the shrimp that fall to the bottom. Petco told me that he indeed eats and has been eating the shrimp. I have considered that he may not be eating since he has only been in the tank for 5 days, or that he may be a bottom feeder. Anybody got any ideas on this? Is there a food that Puffers prefer?