Here is the full list of all 21 Pacifish achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Unlock Dam and Sky fishing
Own all tackle
Defeat all bosses
Own all fishing poles
Reach Fisher level 100
Defeat 50 thousand enemies
Earn 50 million pixels
Complete 50 thousand catches
Earn 500 million coins
Eat 10 million fish
Hatch 10 million fish
Reach fight area 100
Craft 20 fishing pole mods
Get 1000 matches
Find the Black Orb
Reach Market level 50
Spin reels 50 thousand times
Find all five shells
Reach Swimmer level 10
Use 1000 bait
Acquire Sam's journal