Here's the deal. You usually have to go far off shore to get to clear water in the gulf, a 2 hour boat ride plus the 30 minutes drive from Ft Myers to Ft Myers Beach. Or, drive 2 hours to West Palm Beach, take a 20 minute boat ride to great reefs/wrecks with the best visibility in Florida.
There are dive operations that run out of Ft Myers Beach that you could contact. Many of the Ft Myers dive shops plan trips to West Palm Beach because the vis is usually not that good in the gulf. Nothing worse than a two hour boat ride to find 10 ft vis.
I've dove Venice Beach many times, and have found many shark's teeth: megs, mako, great white, etc. The vis can be anywhere from 0 to 30 feet, but usually averages around 5-7 feet. Also, it gets cold in the winter, with water temps as low as 55 degrees. Let me know if you need specific dive locations.