You may note fish gather thickest where there's food. And you'll note with this cam that if there are 2 fish holding in place, a third fish will suspect there might be food, a fourth fish will be sure there's food, and a fifth will buzz the group in hopes of stealing it...but then it all will dissipate in various directions----in individual quest of food. You'll see assemblages for food, for mating, sometimes for protection---and it happens with some species more than others. Herring. I'm not sure there is such a thing as one herring or one sardine, but you know the saying about sardines.