Ceci wants to know more about Magikarp after seeing its statue on the roof of Galaxy Hall.
The Request
Talk to Ceci in front of Galaxy Hall to accept this request.
Complete the Magikarp Entry
Complete the research tasks listed in the Pokédex entry for Magikarp, and talk to Professor Laventon to increase the research level of the Magikarp entry. Do this until the entry reaches Research Level 10. Then talk to Ceci in Jubilife Village.
Reward
You will get 1 Rare Candy.