Nah, they'd all been taught to fish..three of them became masters just from fishing..they just wouldn't do it more than once (from me dropping them in the water) then they'd go straight back to watering non-existant crops.

Seems I've solved the problem though..found the algae fish without the algae and now that puzzle is solved they are fishing AND crops are appearing.

Maybe it has something to do with doing the puzzles out of order?