The study looked at how silver crucian carp affect common carp in fishponds. They put common carp fry in ponds with different amounts of silver crucian carp fry. They found that ponds with more silver crucian carp had smaller common carp and lower yields. In ponds without silver crucian carp, common carp were bigger and the yield was higher. So, having too many silver crucian carp can hurt the growth and productivity of common carp in fishponds.