We did the glass bottom boat Jan 2005. The kids, 3, 5, 6 all enjoyed it because they got to feed the fish. The boat gets pretty rocky so if you get seasick rather easily, I would avoid it. There were fish but the day we took the excursion, there wasn't anything spectacular. If I remember correctly, they take you to a couple of spots where they know fish congregate and you stay at each site for about 10 to 20 minutes. Much of the time is travelling to those sites but it gives you a good overall view of the island and the ship in the background. They provide some good information about the history of CC and it seemed that everybody enjoyed the excursion. There were probably around 30 people on the boat. I would not do it again though.