Does organic fish exist?
Yes, organic fish does exist, but not in the United States. As I write this answer, the USDA has not created organic standards for fish; however, organic fish is available in the United Kingdom. Until organic standards for fish exist in this county, I recommend eating wild fish.
Using wild salmon as an example, I will outline the benefits of eating wild fish instead of farmed fish. According to Environmental Media Services, salmon farmers add antibiotics and vaccines to the water to cut down on the amount of disease spread by the fish living in overcrowded conditions and the waste produced by farming salmon negatively affects the area water quality and harms the plants and animals that live under the salmon cages. Often the feed of farmed salmon contains dyes that make the final product more orange to mimic the color of wild salmon.
Wild salmon live a natural life and are harvested when they are mature. Aside from the more humane aspect of eating wild salmon, wild salmon are rich in oil that is high in Omega-3 fatty acids. Studies have linked Omega-3 fatty acids to reducing several diseases including heart disease, psoriasis, rheumatoid arthritis, depression, and migraines.
There is some speculation that organic fish will not become available as organic standards ensure that animals live in safe and natural conditions and it is doubtful that there are human-made equivalents to the natural habitats of many fish species.