|It is near moonless, and heavily overcast. Away from the small patches of light at the dive centre, it is very, very dark.|
The walk out to the shore is hard work, and rather painful. Im not sure I want to go. My leg hurts from a knock it took earlier, Im tired, and its hard to avoid treading on sharp coral debris in the dark.
But there will be few opportunities to do a night dive in Sipadan, one of the worlds most famous dive sites. Ive done quite a few night dives before, but this one promises to be different.
Once we reach the water, managing the big torch in one hand, trying to do up the fin-straps with the other, it gets easier. We fin slowly over the coral sand, my torchbeam picking out an elegant spotted flatfish. It flips away, only to be caught by the torch beam of my buddy, Hiro, then by that of the dive leader, Leslie, before vanishing.
Towards the drop-off, small shoals of iridescent blue fish reflect the light. Then, suddenly, we are out beyond the reef wall. The torch beam, seemingly almost solid as it is scattered by the plankton, disappears downwards into... nothing. Below us are hundreds of metres of water, regions where no air-breathing scuba diver can survive.
We slowly descend. Each torch makes a patch on the reef wall, so while its hard to see the others, its easy to tell where they are.
The day shift of the reef is over. The cleaning stations, where tiny blue and black-striped wrasse pick the parasites off a queue of multi-coloured customers, have closed. The great clouds of yellow black and white banner angelfish, brilliant blue fusiliers, yellow tangs and smart surgeonfish are gone.
Some can be seen dozing in holes in the reef, the parrotfish surrounded by a transparent bubble of mucus which hides them from predators, the mouths gaping slightly to reveal little white teeth, fused together like bony gums.
In a big hole, a huge Napoleon wrasse stirs slightly in its sleep, perhaps dreaming fishy dreams.
Some creatures work double shifts. The turtles still doze on ledges, or flap lazily past, oblivious of us. An expressionless reptilian eye peers at me from a few centimetres away. Disturbingly, it has no pupil. The effect is slightly Mafioso, like curved mirror sunglasses.
The lumphead wrasse are still there, large blue-green fish a metre or more long, with strange, deformed pinkish bumps on their heads. They have tiny, piggy eyes that seem to follow me with suspicion.
There is also the night shift proper. The reef wall is covered in brilliant orange feeding coral polyps, of which no trace could be seen in daytime. Coral shrimps with long, red and white-banded pincers lurk in holes, their compound eyes reflecting the torch with an orange-gold glow.
Minute, transparent, glass-like shrimps seem to exist only as a pair of disembodied orange eyes which move together, apparently with nothing to support them.
A tiny red crab scuttles, menacing this 2m (in my fins!) rubber-covered invader with its 5mm claws.
A superb nudibranch, velvet black with vivid blue-green spots, crawls slowly over the reef wall, its external gills waving in the current.
All the time, I am conscious of how much I depend on the torches. My own lets me read my gauges and judge from the reef wall whether I am safely holding my level.
The small backup torch in my pocket is comforting, and my buddys and the dive leaders torches beam further reassurance that the inky blackness into which the beam vanishes will not suddenly envelop me.
But thats exactly what we want it to do. We have come looking for flashlight fish, with the twin luminous patches below their eyes which blink on and off, and to see them, our torches must be switched off.
In the reef wall, at about 15m down, there is a depression a couple of metres deep, like a very shallow cave.
As my torch beam swings away from it, I become aware of faint blinking lights at the edge of my vision, at the back of the cave. Almost at the same moment the dive leader spots them, blinks his torch and then switches it off.
My buddy follows suit. I am last, slightly nervously, to switch off.
Instantly, we are enveloped in velvet blackness. No up, down or sideways. Logically I know that I am stable, neutrally buoyant, the right way up, that my ears would warn me of the changing pressure if I really was dropping into those hundreds of metres of water, or starting a dangerously rapid ascent, but the total lack of confirmation from my senses is unnerving.
The dive leader, used to this, puts out a hand to steady me, but after a minute or so my eyes adapt and make out one of the most entrancing, fantastic scenes of my life.
In the top half of the cave, a semi-circle of flashlight fish dance. There are perhaps 20 or 30, each blinking on and off regularly, so that you cannot follow the progress of any individual fish, only an incredible modern ballet of moving, flashing lights.
I know the fish are a few centimetres long, a couple of metres away, but it is difficult to judge the scale; do these lights represent tiny creatures close to me or distant galaxies light years away
Then I realise that the scene is even more fantastic; as my hand moves, it trails glowing blue sparks. A swirling, sparkling vortex streams away from every movement.
The fin-kicks of my companions produce torrents of blue fire. Around our rising bubbles, blue lights twinkle like sparks from a fire, and the bubbles become Christmas tree baubles.
A big wrasse swims by below me, its body outlined in the glowing bioluminescent plankton that are causing these effects, its tail flicking left and right and leaving little swirling blue circles against the blackness of the drop-off, which fade and disperse slowly in its wake.
The scene is straight from a science fiction movie, and at the same time is hypnotic, almost religious in its intensity. It is an experience of utter childish delight, like being a kid with an infinite supply of sparklers on Bonfire Night.
We hang there for some minutes. The torch, which a few minutes ago was my vital connection to reality, becomes a regretful necessity.
I know I must switch it on soon, check my gauges, swim back. But I know it will instantly destroy the dancing world we have glimpsed.
Lit up again, with regret, we fin slowly back. By any normal standards the swim back is spectacularly colourful, especially the brilliantly marked spotted scorpionfish.
But everything pales into insignificance compared to the silent, blinking dance of the flashlight fish, and the glittering beauty of the plankton.
I dont even notice the effort of walking back up the beach, the weight of the tank or the sharp coral.
The adrenalin is still boiling over, and I have to tell anyone who will listen what I have seen.
The image keeps me awake half the night. As I close my eyes, the darkness is invaded by jigging spots, and swirling specks of blue...