You should ask your surgeon about the fish oil. If the surgery will involve the pink cartilage, it has a blood supply and can bleed. The white cartilage is fed by synovial fluid which is why it does not heal very well.
There have been studies that show no risk.
http://www.omega3innovations.com/blo...al-procedures/
Google 'stop fish oil surgery.'
But, there is no reason to push it. Stop 5 days before and resume 5 days after.