Hi Mr. Williams,
That is a tricky question and depending on who you ask, you would get opposite answers. As a general rule, grouper are known to feed better in the day then at night. But that doesn't mean you cannot catch them at night. They can be caught at night. Snapper on the other hand are known to feed very well at night. Yet you can still catch snapper in the day. I know many Captains and commercial fisherman that fish for grouper at night, especially around the full moon. They do very well catching grouper. Maybe it is because they are fishing a lot at night so they catch more grouper. Maybe in the summer because the water temperatures are cooler, they catch more grouper at night, if you get what I am saying.
Groupers like this one are just waiting for you night or day.
The circumstances and conditions have a lot to do with it. While the consensus of anglers would say that grouper bite and feed better in the day, it may be because the majority of grouper fisherman fish in the daytime. So this is my humble opinion. I would bet that you can catch grouper at night, using the fishing conditions and circumstances to your advantage. Such as fishing in and around the full moon, or fishing on a better tide where grouper generally feed better than on a super-fast moving tide where it's hard to keep your bait in the strike zone, and more difficult for the grouper to ambush bait because of the fast tidal current.
You could also try fishing in the grouper’s comfortable temperature zone. Or even where there is an abundance of forage that the grouper is currently feeding on. The same can be said for daytime grouper fishing. That being said, I would not let that stop me from trying to grouper fish at night and form my own personal facts and observations. I hope this helped. Oh yes I have caught grouper at night, but not as many as in the day. But that is because I fish for grouper 99% of the time in the day!
Thank you, for sending in your questions to the online fisherman. "Where you count more than the fish."
Captain David M Rieumont
The Online Fisherman Inc.