For what its worth, I saw Dr. Strum recommend fish oil in a P2P post. He recommended getting an essential fatty acid profile test (available from Mayo Lab), and using the information derived from that test to determine the dose of fish oil.
Age 46. Father died of p ca.
My psa starting age 40: 1.4, 1.3, 1.43, 1.74, 1.7, 1.5, 1.5