Maaya Thila

Most dives start by dropping down a line from a reef-top mooring onto a crown that most accounts put at about 6 metres, though one guide places it at 8 to 10. The top slopes gently to about 12 metres, and then the edge falls away below 30. Blue-stripe snapper face into the current, a resident turtle grazes the coral, and nudibranchs, flatworms and the odd frogfish repay a slow look on the crown. Over the edge the pinnacle is ringed with caves and overhangs, and the big cave on the north side holds the densest fish life. A big rock on the south side has a metre-wide swim-through at 24 metres depth.

Whitetip reef sharks park on the current side, and whitetips and grey reefs together often number in the teens or beyond. One operator speaks of dozens of whitetips circling the reef. Dogtooth tuna and great barracuda hang off the blue, and spotted eagle rays pass now and then.

At about 80 metres across, the thila can be circled in one dive if the current is favourable, though divers often spend the whole dive on one face. With little current you return to the mooring line. When the current makes the line unreachable, the dive ends in a gentle drift.

After dark the crown becomes the stage. Vast numbers of fusiliers arrive to feed, the whitetips constantly buzz the reef hunting them, and trevally strike in short bursts. Stingrays and morays patrol, and the quieter faces give up parrotfish in their mucus cocoons, octopus and the occasional Spanish dancer. One travel writer says the whitetips use divers' torch beams to find sleeping fish.

Fusiliers pour onto the crown after sunset, and the sharks that patrol the pinnacle all day go to work on them. That is this thila's own character: a small, near-circular reef where the hunt happens in a space you can take in. Operators describe it as a protected marine reserve under the Maldivian government.

Accounts from divers put the whitetips at around a metre, so numbers and behaviour carry the dive, with size playing no part. By day the sharks favour the side where the current runs hardest, and the night dive waits for it to ease.

The current is very changeable, so the experience and discretion of the crew matter. In little or no current one guide rates the site suitable for all diver levels, and the crown lies within Open Water depth. When the current is strong the recommendation becomes Advanced divers only, with a safety float deployed. The swim-through at 24 metres and the walls below 18 metres are Advanced depth.

One travel writer calls liveaboards the most consistent way to dive it at night. Briefings stress light discipline and keeping the group together, and a primary torch, a backup and a signal light are the kit for it. The night dive goes ahead only in slack current, so the crew's reading of the water on the night decides it.