There is good reason why fishing charters are so plentiful in Key West that they are categorized into Flats/Backcountry Fishing, Light Tackle Fishing, and Offshore Fishing. 
Thousands of anglers come to Key West and join highly skilled captains to fish the “great blue river” a 90-mile-long trough of deep water beyond the reef, or the shallow flats and mangrove islands, or the inshore channels. No matter where - - all the fishing is incredible!