We are wondering how this will rate. In Aitutaki the lagoon doesn't have openings to open ocean so there were no issues with sharks or anything... and a reasonable variety of smaller fish.
Has anyone done the "shooting the pass" snorkeling in Manihi? It sounds very interesting but slightly scary. Is the current bringing you into the lagoon or shooting you into open ocean? What sort of stuff do you see on the coral wall, etc.