Came a Mormon also be a wiccan?

No. Being a member of the Church of Jesus Christ of Latter-day Saints (commonly called the 'Mormon' church) means that you believe that the Church is the only completely true religion existing and the only way to salvation. If you are a baptized member of the Church, you are in violation of your baptismal covenants to be an active member in any other religious movement. If you are a Temple Endowed member of the Church, you are in violation of your Temple covenants. You may visit the worship services of other religious groups on occassion, but cannot become a member of these groups.