Hi Greg,
I've often said that I can't tell you what they will be, but if you spend enough time out on the water, you'll see and experience some really cool stuff.

In this case, one of the things my wife and I like to do when anchored out is to shine a light down into the water and see what is attracted to it. Sometimes, not much comes along before we get bored and turn to something else. Sometimes though, really cool stuff. I did the HaHa on a friend's boat last fall and we spent a little time out at the islands near La Paz afterwards. True to form, most evenings after it got dark, I would shine a bright light down into the water. One night, a small manta came by and we watched it feeding under the boat for at least half an hour. The next night though, a whole bunch of them were there, so we decided we had to join them. Another night, a small needle fish (about 2 1/2; long) was among the visitors. He kept hitting the surface right under the light as he was feeding on the small stuff attracted by the light. Al's boat is a Ranger 33, with a fairly low freeboard back at the cockpit and Al was able to reach down and grab him by hand as he swam by.

By the way, in our travels, we have gone through many, many flashlights. None seemed to last too long. That is until we stumbled on these (see photo). They are uber bright (bright enough to shine up on the sail to illuminate it for a nearby boat to see), and because they're waterproof, the contacts don't fail from salt air corrosion. They run off of 4 AA batteries and when I brought the boat from New Zealand in 2012, I think a single set of batteries lasted the whole way. I used to use a head lamp when I had to go forward at night, but now I just keep one of these in my pocket. If I need to use both hands for something, I just hold the flashlight in my mouth.

Their only weak point is the switch. On two of them, it has broken off, but at less then $10 for the light (the one on Ebay I grabbed the image from was $5.02 with free shipping), I keep a couple of spares onboard. I also have them in the glove boxes of our cars, in the nightstand by my bed, etc.