The positive aspects of fish oil are usually pretty much insane, they are usually almost “uncountable” you really can’t ever know the exact positive aspects because each individual reacts in another way to any “natural” material, but almost across the board, people who take fish oil are usually healthier and happier.
Fish oil is mostly an omega 3 fatty acid, there are usually other variations of fat as well.
Some examples are usually saturated fat, trans fat, omega 6 fat, monounsaturated fat, polyunsaturated fat (which is for the most part the omega 3 and 6 fats.)
All of these fats have an effect on your system differently, omega 6 is for the most part an inflammatory type of fat, and omega 3 counteracts the omega 6 (one of fish oil benefits)inflammatory response.
Though omega 6 is inflammatory it is still important to get some omega 6 into your diet because you still from time to time need an inflammatory response, just not a chronic one.