Master Angler
Very rare1.8%Catch every fish.
Every fish in the collection tab, including the five legendaries (Legend, Crimsonfish, Angler, Glacierfish, Mutant Carp) and the crab pot shellfish - though you can't do it on pots alone. The extended-family legendaries from Qi's quest do not count, mercifully.
The shape of it: fish each season's exclusives as they come round (season, weather, water and time of day all gate spawns - check the collection tab for gaps), do the mines levels for the cave fish, the Desert, the Witch's Swamp, and Ginger Island's handful. The legendaries want fishing level 10, an Iridium Rod, trap bobber and Seafoam Pudding buffs - Legend in the mountain lake (rain, spring) is the nastiest.
Miss a season's fish and it's just a year's wait, not gone - nothing here is permanently missable. Completing the collection also earns a Stardrop from Willy (