My wife and I rented a tandem last week in Cape May, NJ, and didn't have any problems (either with navigation or marital). We (I mean "I") didn't fish, so I can't offer any suggestions for fishing tandems.

But... I am planning on getting two singles (I'm this close from finishing a cedar strip one) because I want to go alone sometimes.

If you haven't, check out this site: [url=http://kayakfishingstuff.com/:069c1]http://kayakfishingstuff.com/[/url:069c1]
They specialize in fishing kayaks and could give you some great pointers if your looking to primarily use your kayak for fishing. They highly recommend talking with people that fish out of kayaks for opinions and not general kayak shops as there are certain characteristics that make a great fishing kayak.