I thought shellfish was haram.....................
Difference of opinion. I think most schools consider it Makruh, which means that it's not sinful to eat, but it's beneficial to avoid. But I've heard opinions that it's haram, and halal. I generally avoid it unless I have no other options.
also
When the first Christian missionaries arrived in Japan newly-converted Christians were forced to return to Buddhism with the threat of death if they would not trample upon images of the Virgin and child.
Christian converts in India have been forced to return to Hinduism throughout history. Some temples have "re-conversion" rituals. In Karnataka India violence between Christians and Hindus has escalated since 2006 and just recently resulted in Hindu Nationalists forcing conversions on their Christian minority.