Hi If we talk about medical science & researches, then this has been proven completely a myth ages back. But if we talk of ayurveda, then yes they do believe in it. So my scientific advice as a Dietitian is that it will cause no harm. Go Ahead! But being an Indian on the contrary I would say that avoiding milk with fish is no big deal. So there is no harm either in avoiding. So it's upto you to follow Medical Science or Ayurveda. Ayurveda is India's age old science & doesn't evolves much over time whereas Medical Science keeps on evolving and is evidence based science :)