Taking fish oil will slow down the absorption of the whey. The time to digest when taken alone is:
whey 2 hours
casein: 5-7 hours
egg 3 hours
soy 5 hours
Therefore you don't want to take the fish oil when you want quick absorption such as in the morning when you wake up or after a workout.
As long as you have a solid diet and take a general multi-vitamin I would not worry and would advise against supplementing with b-vitamins; unless of course you are correcting a deficiency but then you should seek professional advice for your particular situation. B-vitamin deficiencies are very very rare especially in developed countries and it is most likely a secondary deficiency (poor absorption due to physiologic factors or drug/nutrient interaction) and not a primary deficiency i.e. lack of dietary intake.
