I remember a study saying that treating IBD needs a higher intake as normal recommended serving sizes, up to 4 g of EPA & DHA per day. You'll have to check the concentration of your oil and increase the dose step by step to see if / when you have a positive effect.
Are you considering conventional therapy with budesonide and / or antibiotics also? I'm currently trying Omega 3 fish oil sofgels, in combination with a low dose of the mentioned meds, but I can't really tell if it helps me.