To add to this, I've read recommendations from public health orgs to eat no more than two portions of oily fish a week, and minimise consumption of especially high sources like tuna steaks.

Some consumption is still recommended for omega 3s, though there are algae-based supplements for EPA and DHA as well as the fish ones. Flaxseed and some nuts are great sources of ALA, but afaik its conversion to EPA and DHA isn't great and consuming all three is a good idea.

(Disclaimer: I am not a nutritionist. Verify things yourself before making dietary changes.)