Pescetarian is from the latin word pesce(fish).
It is a natural diet that has been practised by many indigenous groups for millennia particularly nations that live by the sea.
Pescetarianism has been acknowledged by nutritionists and medical professionals as one of the healthiest diets due to the abundance of the long-chain omega 3 acid in fish oil, worth noting is the long-chain type can only be found in fatty fish and not in some nuts or seeds as some Vegetarians like to believe. Pescetarian diet is very similar to the famous Okinawa and Mediterranean diet. Studies have also proved the significant role long-chain omega3 acid has in simulating brain cells resulting in better analytical thinking and response. Medical research has acknowledged the role of long-chain omega3 in prevention and fighting of cancerous cells.
As a natural diet, Pescetarianism existed before white man invented unnatural diets as what he perceives as natural or humane like Fruitarianism or other unnatural diets which are likely to cause illnesses and/or malnutrition due to the lack of sufficient or adequate nutrients.