Zanzibar is not a country it's an island in Tanzania . So you are looking for visa on arrival in "Tanzania" and yes for Ethiopian citizens it's visa on arrival you can just buy a place ticket and pay visa fee when you get there and have your passport stamped. Also le Lela gizem you can Google "sherpa travel" add your passport country and to and from you are travelling to and it will tell you what you need and if it's an evisa give you place to apply so it makes your life easier