This may be a bit far for you, but the 1000 Islands are about 4 hours east from Buffalo. Cape Vincent has a great park for snorkeling and scuba.
I've seen gobbies, yellow perch, white perch, black crappie, dogfish, channel catfish, little and big mouth bass and zebra mussles. Lots of plants as well.
Her's the big bonus -a ship wreck!! This wreck is about 60 - 80 feet long and you can clearly see the ribs of the fish. It's off the end of a now submerged pier. The whhole thing is maybe 30 ft from land and the wall is very shallow in places and swarming with fish.
The water is crystal clear, (thanks to invasive zebra mussels) so visibilty is great. I also like Cedar Point State Park. Same fisk essentially but more boat traffic. Go around the bend away from the beach to snorkel. Extra bonus is showers and changing rooms are available in the park. I think most NYS parks are 7$ to get in.
