There is a ceremony related to Saint Cethleann that requires rare fish. Would you mind helping me obtain some, Professor? You can fish by speaking with the fishkeeper at the fishing pond.
Catch a fish for the ceremony and bring it to Flayn. Head to the fishing pond with the bait she gave you, and speak with the fishkeeper to try out fishing.
  1. Accept the quest from Flayn.
  2. Catch a fish at the fishing pond.
  3. Report to Flayn.
How wonderful! I am certain Saint Cethleann would be most satisfied by this fish. If you ever wish to fish again, simply let the manager of the fishing pond know.