The generics may or may not be identical to each other...But they are NOT identical to Vascepa, which has a patented gelatin capsule preventing the oxidization of the vital pure EPA .
The FDA only requires what they call "Bioequivalence" (BE), which for OMG-3FA's is pretty lax. The main factor which distinguishes VASCEPA from GV is the rate at which the active ingredient and the affected targets (lipids) become oxidized. There are tests for "Oxidative Stress", but these tests are NOT required by the FDA to meet their "BE" standard.