The reliable source explains in detail that the production crew after about 5 hours of struggle managed to catch a big fish. Salman somehow knew about the plan and reached the lake where fish was being poached. He immediately stopped the activity and let the fish go.
It seems Salman is quite inspired by the nursery rhyme ‘Machli jal ki rani hai jeevan uska pani, bahar Nikalo ge oh mar jayegi’.