In stool, see yellow nickel sized oval floating(looked like lupini bean), poke it, it just mushed, what was this? undigested fish pill?

Relax: There are may things with undigestible hulks such as favs beans, sausage/hot dogs, pills, small peppers, olives, corn, seeds and nuts in general. Unless you are having some dietary issues, abdominal pains/cramping regularly, or constipation that causes problems, I suggest you stop worrying about what's in you poop. If you are concerned, your gastroenterologist can explain in better detail.