farm raised trouts - elusive prey

Every year the Texas Fish & Wildlife releases thousands of farm raised trouts into ponds in state and municipal parks all over the state. Catching these should be as easy as shooting fish in a barrel, right? Not when you showed up a week after the stocked the fish and it's raining cats and dogs. It's the fourth time in two years I bought a $10 one day fishing pass and not catch anything. The fifth time's the charm, I can feel it.