It's just a Red Herring

 Generally , as this is all about the "Red Herring", you should choose 1 Red Herring and as many Grey Herrings as you require to make up your school. There are no rules and you may want 1 Red and 3 Grey or you could decide on a large school for maximum impact. Fish are sold individually .$30 each and 180 mm long . 

8 Grey and 1 Red Herring

10 Grey and 1 Red herring