No. Fish farms might be unattractive, but I' have personally traveled all over the world, and I've never once seen a fish farm. When they are placed in an appropriate area, and they are able to keep out of sight and out of mind, tourists would very rarely stumble upon a fish farm.
The major advantage of fish farming is the ability to raise fish in a clean, controllable environment. Wild catch fishing is far more difficult to maintain safe fishing conditions for the workers and clean consumable product for market. Tourism isn't affected by farm fishing and opens more open sea to tourism.