Although Japanese love meat－actually people are quite inclined to meat than fish－Japanese traditional food culture is invariably based on fish. As simplicity is always the main idea of Japanese culture, fish as well is to be prepared simply; grilled, poached or steamed using simple seasonings－hardly fried, thus Japanese food is considered healthy.
“肝油” (かんゆ, Kan yu) is cod liver oil. This is a nutritional supplement derived from the livers of cod fish.
The tap water in Japan are being disinfected with Chlorine so you can drink it with no problem. There are only 15 out of 196 countries in the world that tap water is safe to drink.