Lime juice does not kill parasites. The pH of lime juice is 2.The pH of hydrochloric acid in your stomach is 1...and stomach acid does not kill parasites either. If you eat freshwater fish raw or undercooked, you are risking parasites like tapeworms, roundworms, flukes, thornyhead worms as either the definative host (adult worms) or intermediate host (encysted metacercaria) in your organs.