A bit of googling on the phrases you quoted gave as top hit the page http://www.koffeeklub.net/shayenne/fishes.htm and the info "The song If Wishes Were Fishes was composed and sung by Scottish-born Australian folk singer, Eric Bogle", along with the lyrics, of which these are some:
And I wish I was young again, my song still to be sung again
The sweet tunes of my life have gone sour and off key.
Writing my tidal rhymes
trying to turn back time.
And if wishes were fishes we'd all cast nets in the sea.