No there are many dive centers on Rangiroa, Tikihau and Fakarava. I still prefer Topdive which has dive centers on both islands... and they have a new owner who is doing a lot of equipment upgrades on both atolls... so there is plenty of opportunity to dive in most of the inhabited atolls... Topdive also has a inter Island pass which will give you some break in pricing. I still think the diving in Fakarave is the best diving in the world.. and I've been to many locations...