I have been to Cuba twice over the past two years, and fished both times. First time was in Playa Cayo Santa Maria, which is just outside Veradero, and the second time was in Sol Cayo Coco. Most beach resorts will offer their guests some form of fishing adventures, it all depends on how much you want to spend.
IMO, beach fishing is your best option. The resorts really gouge the clients when it comes to fishing adventures. A full day excursion usually costs between $270-350 CUC per day. I know that the CUC is not going to be used for much longer, however for now, with exchange rates the way they are, its quite pricey to hire the guides at the resorts.
The first year I went, in Playa Cayo Santa Maria, excellent resort by the way, I made the mistake of bringing none of my own fishing gear with me. The fishing equipment they have in Cuba is horrible, all of it is left behind for the locals by Canadian tourists. It is impossible for them to purchase anything locally. I made friends with the beach staff, and convinced them to take me out on the Hobby Cat catamaran for a couple hours. Cost me $70 CUC for 2 hours, I hooked a big Baracuda, lost it while trying to land it, and landed a big Grouper. However I was on a small sail boat with a local who didn't speak a word of English, kinda awkward, but still a good time. Awesome experience.
The second time, in Sol Cayo Coco, was a bad resort, wouldn't recommend going to that part of Cuba. It's only a 15 min drive from the airport, which is nice, but it's an old and run down part of Cuba. All of the resorts in that part of Cuba were built in the early 90's, and now they are all run down and falling apart. But the beaches in Cayo Coco are amazing and endless. This time I brought some of my own spoons, spinners, line and hooks with me, and used them on the beaches. I borrowed a rod and reel from the local beach staff, with the promise that i would leave behind all my gear when I left. I would chuck metal on the beaches, with limited success. Landed a couple small Needle fish, and a couple Jacks. Nothing special, but still fun and worth the pictures. I did watch a few locals land some big Barracuda off the beaches, just nothing for me. Early mornings and late evenings were the most successful times of day..
If you and the wife are looking to party while in Cuba, I would recommend Veradero. If you are looking to relax on a beach, I would go to Playa Cayo Santa Maria. Bring all your own gear with you, and you won't be disappointed. The resorts may be cheap, but they do everything in their power to get every dollar from you while you are there. Tipping the staff is optional, but a peso here and there to the beach staff, chamber maids and the bartenders goes a long way.
Bring your own mugs, the small plastic cups they give you are a joke.
Both times we traveled in October, which is the end of hurricane season there, so it's off season and quite a lot cheaper. The resorts are basically empty, which is awesome. Having the beach to yourself is amazing. I couldn't imagine it during peak season, would be far too busy for my liking. From December to June it's primarily Canadian travelers, in the off season it's mostly rude Europeans who want nothing to do with you. Which was totally fine with me..
Sorry for the wall of text, just kept going. Hope that helps..