The 3 rarest fish in (Animal Crossing) are the Arowana/Golden Dragon Fish, Arapamia and the rarest of them all the Cruceathan.
Time of day-mid day
Time of day-after 8pm
Shadow-Huge(Bigger than U have ever seen can clog up stream when sideways)
Weather-clear days NO rain
Time of day-9am to around 6/7 pm
Shadow-same size as Arapamia/Huge
Weather-Rainy days !ONLY!