My yellow nattereri acts pretty much the same as the other types of pygos in my shoal. He is the largest and has claimed more territory in the tank but the others will defend their territory just as vigorously. I dont think he eats proportionately more than the others, they all are very good eaters. I dont think my shoal is skittish and the same stimulus causes the same reaction within the shoal, and when spooked the shoal will all group together. My yellow and my little red are the most adventurous, both coming to the front of the tank when I wave to them. My personal opinion is that people tend to exaggerate their fish and how they act. Maybe it is that I try to enjoy my fish and not over analyze them so I dont notice a huge difference in the pygos, viewing them more as a shoal. There is however a large difference in pygos vs serras.