Even if you eat enough fish which contain alot of omega 3 I think it's important to supplement with some extra.
In todays society we eat alot of food that contain more omega 6, sometimes up to 20 times more!
It's very important to have a good balance between these fatty acids if you don't want to end up getting chronic inflammation.
It would be best to just stop eating crap with to much omega 6 but it's kinda hard since most meat isn't from grass-fed animals and the fish isn't wild caught.