Yes, this is a good idea. Farmed salmon in the USA was fed in such a way that they had much diminished Omega-6 content versus wild-caught. However, I am not sure if practices have changed since I first looked into it, which was in the later 2000s. It is harder to track down suppliers to verify in the USA because of the supermarket phenomenon here.
There are some GMO plants that like camelina that synthesize DHA/omega 3s and a soybean that produces other long chain SDA which are omega3 DHA/EPA precursors, which could be used as farmed fish feed to help get them back to natural 3:6 ratios but the govs make it hard so they keep making unhealthy fish and feeding bycatch