There's also the quest if you've not done that yet. (hit the yellow ! in the middle of the map after selecting Go Fishing).
For the Quackaphone, make sure that Tutorial Mode is switched off in the options, then select Go Fishing. On the map double tap the lighthouse and you'll see the beam switch on. As the beam passes over the woods you'll see a duck appear for a very short while. Tap on the duck quickly to access the Old Pond in Quackaphone mode.