I have a freind who gets chronic anxiety soon after taking omega 3 supps (1gram ish). Any idea what that could indicate as to a health problem?

An allergy to something in the product could cause this.  Anxiety is most often caused by a build up of lactate.  But is can also be triggered by excess epinephrine (adrenaline) such as during an allergic response and a lack of acetylcholine to balance it out.

Epinephrine can also be released in response to the histamine produced in the flesh of some fish when exposed to sunlight.   Tuna and mackerel for example can generate histamine if sitting on a dock on the sunlight.

One way to find out is to take some quercetin, 400-500mg of pure quercetin,  prior to taking the fish oil.  The quercetin will counter any allergic responses.  Therefore, if this stops the problem then it would indicate epinephrine induced anxiety.