I will second the suggestion by Tom L - the Snorkeling boat tours are just "ok" in my opinion. We've been on Oceanus and Cabo Rey, and they both do a good job if that it to your liking. You spend a lot of time waiting in line to try to find the right gear, then spend an hour bumping into other snorkelers. Even on those trips, we bring our own snorkel & mask. The tropical fish love bananas, so take a few with you - break off in very small pieces and watch the fish go crazy.
For fishing, we recently used Redrum for the first time, and had a great experience (following is my review:http://www.tripadvisor.com/ShowUserReviews-g152515-d639404-r156379349-Redrum_Sportfishing-Cabo_San_Lucas_Los_Cabos_Baja_California.html#REVIEWS
One other option, on the pricey side, is to charter a boat to do a combination fishing & snorkeling trip. You can check with some of the fishing charters to see if they offer that option. One that I know of is Winner7. We did a fishing trip with them two years ago and had a great time. They also gave us the option to stop and snorkel for a couple of hours. It is a truly all inclusive charter, beer water, a hot breakfast, and a taco bar for lunch (and if you catch tuna - the crew will make sushi & ceviche for lunch). Dave Carter & his wife Kathy are from Arizona and own the Winner7 boat, and have a local captain & first mate.