Luca Brazzi sleeps with the fishes ­— that’s a line from The Godfather, of course. But neither Luca nor anyone else really sleeps with fishes because it is debatable whether fish truly sleep at all.

Scientists agree that fish do rest and conserve energy, but do not experience sleep in the way humans do. To have sleep, one must have an associated change in brainwaves. Since the brainwaves of fish don’t change when they take a respite, their resting behavior is not considered true sleep. Fish also forgo REM (rapid eye movement) sleep, and pajamas and flannel sheets are not part of the equation either. Surprisingly though, in studies, fish have been know to exhibit symptoms of sleep deprivation and insomnia.

It is difficult to tell when a fish is even resting, since most fish have no eyelids. Sharks are the exception to the eyelid rule, but I wouldn’t want to get close enough to them for a wake-up call. One scientist noted that you can tell a resting fish by the movements of its mouth, jaw and gills as it respires, essentially its breathing rate and pattern.

The animal that comes closest to resembling a mammal in its sleep habits is the reef-dwelling parrotfish. While we don’t have these in our waters, their behavior is immortalized in a book called When Do Fish Sleep?, part of a series of books called Imponderables by David Feldman. These fish hole up in crevasses and secrete a mucous around their body, much like a blanket, then go to ‘sleep.’

Sleep cycles — mine, not fishes’ — may explain why I still haven’t caught a fish this derby. Readers of this column know my penchant for sleep and lots of it. It seems that whether fish sleep or not, they are most active during the times when I am in my bed sleeping. So, although I hope that my luck will soon change, my only brush with derby fish so far is in the pages of this newspaper.

The notoriously active nighttime fish is the striped bass. When they are in Island waters, striped bass are nocturnal fish that are generally active when I am sleeping. According to the Massachusetts Division of Fish and Wildlife, “angling at dusk and dawn provides the greatest success during most of the season, but night fishing is often best during the midsummer.”

If you are going to sleep at night and fish during the day, then it is better to be on the prowl for the other derby fish: false albacore, bonito and bluefish. No matter how tired you are, you wouldn’t want to be asleep when you’ve got false albacore on the line. This fish will run out your line whether you are paying attention or not. And if you are trying to catch a bluefish, sleep will be the last thing on your mind. Bluefish are notoriously aggressive and go into a feeding frenzy, but never a sleeping frenzy.

Perhaps it is only the night owls who succeed during the derby. The resident barn owls at Felix Neck may be able to tell me — they are awake then. But maybe, I could take a lesson from the osprey as well, and try to convince myself that night finishing isn’t the only fishing. I can keep hoping that it is not only the sleepless that catch fish, and that good things come to those who bait.

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.