A while back, when Biscayne fly shop was on US1, they had a few pics on the wall of bonefish caught at night and I was told it was with a full moon. Not sure how much of that was BS vs how much of it was true.
Absolutely they feed at night.
Look at the size of their eyes. They're not that big for daytime vision. Their prey, particularly crabs, are way more active at night. 2+2=4.
When I have fished until dark I find fish very shallow and still heading into the mangroves. They're not heading in there to sleep. And they're still there very shallow before daybreak.
When out before sunrise trying to pre-position myself for daybreak tailers, I hear and spook plenty of fish in near total darkness.
In the Caicos, the locals all had stories about bait fishing for bonefish after dark........indeed it was their preferred time to fish.
When fishing for tailing bonefish at dusk I do notice a drop off in success and sightings once the light has nearly disappeared but the same thing happens with striped bass......only to turn back on with a vengeance over the next hour. I suspect bonefish do the same.
As for to how to efficiently target them on flats in the dark without lining and spooking them? Therein is the rub.
Forgot to mention... years ago (late seventies, early eighties...) there were one or two articles (in Florida Sportsman, I believe) about actually fishing tailers up super skinny at night - on full moon nights... Haven't heard or read about that sort of stuff in years now - and it's something I've never tried... I imagine it's still very do-able and I'll bet that anyone knowing about this is very smart not saying the first word about it....
My biggest bone ive caught was in Harbor Island. I had chased them early in the morning while they where tailing or cruising, not a bite. I did this for a couple of days with no success. One evening late when it was almost dark they where tailing up near shore. I cast into them hooked one and it broke off. Threw another fly in there and landed a 9.5 lb. By the time i landed that fish it was dark