Tariku became the 5000 m junior champion at the 2006 World Junior Championships and was fourth over the distance at the 2006 IAAF World Athletics Final. He took the 3000 m gold at the World Final, however, having also run the third fastest 3000 m time of the season (7:29.11) in a second-place performance behind Isaac Kiprono Songok at the Rieti Meeting.