Well, even if your panda ate a piece of poop in an isolated event, one cannot believe that poop is enough food, or enough maintenance for a tank. Cories are a schooling species, so at least 2 more are needed, and they have nutritional needs not met simply by scavenging. They need to be fed intentionally either bottom sinking wafers, shrimp pellets, or frozen foods (like bloodworms or tubifex).