Sadly I’m with you all. I joined late playing the game (only 6 months playtime) and am stuck on the magic carp quest… none spawn in my area even with weather boost (rain) right now it’s all Merrill’s, and woopers. Magic carp are no longer appearing in gyms either (for raids) I have been trying to keep track of every raid within 15miles of my house and nada. Even raided an absol and got a shiny. No more magic carps. Seems I am doomed to have as pet for forever until I can walk/earn all the candies.
As Jormdeworm said.
I believe save the rare candy and walk will be the best option.
For now we will not see magirkap because the Celebi’s event, they are spawn.
Save your tickets for Magikarp raid for the future, as soon as Celebi ends I hope the normal pokemon will return with magikarp as well. Save your pineco! Nothing to do.