There are several T nation articles suggesting mega-dosing fish oil (30-45g), even in the bulking phase. The improved insulin sensitivity, fat oxidation, blood flow would have to be balanced against the anti-inflammatory properties of fish oil, which may counter against high dosages in bulking.
However, given that the evolutionary ratio of omega 6/3 fats is something like 2/1 to 1/1, the current medical recommendations of 1-2g of EPA/DHA per day seem inadequate.