the reason your weightlifter friends are taking 8-10 a day is to fight inflammation from a heavy workload, at least i would assume. fish oil is a great anti-inflammatory, but omega-3 fatty acids are important for many other functions on top of that. everyone should be getting a decent amount of omega-3 fats in order to keep their body functioning properly.
some scientists and researchers theorize that one of the reasons we have seen such a large jump in the prevalence of degenerative diseases and obesity is because of a lack of polyunsaturated fats (omega-3s), and a steadily increasing ratio of omega 6:omega 3 fats, causing more inflammation.
i would highly recommend that you at least take 1000 mg of fish oil per day, possibly more. a decent one-per-day fish oil capsule will have close to 1000 mg, so start taking those with your breakfast or dinner. you most likely don’t need 8-10 per day like your weightlifting friends unless you have a training intensity close to theirs, but 2-5 capsules a day wouldn’t kill you.