Will my serpae tetra eat my sick,old or elderly guppies?

i have a 400 gallon tank and it has 8 serpae tetras,guppies,2 dwarf cichlids,1 pike topwater minnow and a britstlenose pleco and i was wondering if my serpaes would eat my sick or dying guppies because i sought of want a food chain and also the guppies are the wild variation and only reach an inch in length.