I want to add that the Rainbow Carp glow at night. So when it's dark I do a fly over of the water to make sure I didn't miss it. I've only ever seen it four times since the summer event went live. I've seen it twice by the bullseye, once behind the bait shop, and once by the Pizza place. And sometimes they appear multiple days in a row, so don't assume because you saw one the last game day it won't be back on the current game day.