The Thila (underwater mountain which does not reach the surface) is next (gadhu) to a sandy reef (dinolhu) on the west side of theNorth Ari Atoll, with a lagoon which is also a feeding ground.
The main cleaning station is on the top reef and is in about 8 meters deep and surrounded by sand. I recommend you to take a reef stick, because there will be current. Normaly when you jump in the water, the Mantas will disappear. After 5-10 minutes they will come back and they will stay! A lot of fish is there, and there is normally no reason not to spend the whole dive over there, but what I preferred was to go to the very outside of the Atoll and drift along the edge, because the whole edge was one big cleaning station with small overhangs full of soft corals, nudibranches, napoleaons, sharks, turtle, eagle rays, well everything you want.On one dive I even had troubles deploying my surface marker balloon due to Manta rays circling around.
This dive site is everything but an easy dive. First of all there is current and second of all, ther is always a bit of surge going on. Coming into the water and out of it is not the easiest thing, but well worth it!