It will shine still brighter when night is about you. May it be a light to you in dark places, when all other lights go out.
Once the sun has dropped below the horizon, you can continue to dive, you just have to bring your own light with you. Night divers normally have a large, bright dive light and a smaller backup dive light. Some strobes have a modeling light which can act as the main dive light, but you still need at least one other dive light.
In someways it is actually easier to take photographs at night, the fish are often dopily lounging around while crustacea like shrimps have come out of their crevices and scuttle about the reef.
Diving at night, with or without a camera, is a strange if not surreal experience. It’s a bit like being in the middle of an Alien movie: labored breathing, flashlights peering in to the darkness, the ease at which disorientation sets in, and an awareness that something toothy might be lurking just outside your field of vision.
Photo-jacking / photo-bombing is the phenomenon when a stranger decides to jump into background of your photograph to ruin (or possibly improve) your shot. It seems to be quite common during night dives when using strobes with bright modeling lights. If you spend too much time photographing a particular subject, dozens if not hundreds of other little creatures, like moths to a flame, will get in on your shot. This is annoying if you want a clean background, but amazing as you don’t clearly see the plankton until they’ve been illuminated by the bright strobe. There are some lovely iridescent copepods in the above shot of two nudibranchs.