It makes a big difference in tidal water. Full moons equate to bigger tides which means more current that the predators use to their advantage to catch baitfish.
Given the option I’ll fish a few days before the full moon and the following couple of days after. In reality I fish whenever I’m on days off and the swell is small enough I can get out there.
When I was researching where to catch swordfish out front here I found a study done over a 12 year period on the longline swordfish capture. One of the things they graphed was the moon phase. For every fish they caught on a new moon they caught 2.5 fish on a full moon. This is the resulting data from millions of hooksets over many years.
I never noticed any difference in freshwater. The fish were always biting when I had hooks in the water.