Yeah Garrett... no one ever said it was smart but that's what they do. Use other drugs to try to take the side effects off other drugs. Because the drug that's superior to them all can't be patented.
As far as I know vitamin K can offset the anti-coagulent properties of fish oil completely since vitamin K is a cofactor to thrombin (and an antagonist of warfarin blood thinning agent like fish oil, heparin, etc.)
You want about 3-5g of EPA+DHA per day. That's the omegas 3s in the fish oil that you want. Just capsules (if they're 1g) aren't gonna cut it.
If you're taking the .5g EPA+DHA per 10 lbs of body mass (via Robb Wolf if you're really jacked up with inflammatory issues) then I would definitely say you need VitK, but I'm not sure you need it with 3-5g per day. It depends on the individual though. Just eat a crapton of brocolli or take a supplement of vitamin K.