THEME:   backward spellings of fish noted for swimming upstream   
GOOD ONES:     
{two words} phenomenon that's graphically demonstrated five times in the puzzle   SWIMMING UPSTREAM   
Old ring leader?   ALI   
One who has class?   PUPIL   
Zombie leader?   ZEE [the question mark gave this to me right off: wonder if it's needed]      
BTW:   Nonspecific journal opening   DAY ONE [I'd say that's specific; it's not Day Two]      
I had almost completed the puzzle before I realized I needed to spell the fish backwards; and not being a fisherman, only SALMON was easy.      
RATING:    
 
  
 
Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun