Do fish oil tablets help regulate good and bad cholesterol ? at what level of bad cholesterol should one start medications instead of relying on life style changes ?

A tough question: Guidelines: "Large-scale epidemiological studies suggest that individuals at risk for CHD benefit from the consumption of plant- and marine-derived omega-3 fatty acids, although the ideal intakes presently are unclear." Basically, that's saying that they help but there's no clear evidence to suggest when or how to take them optimally. Fish oils decrease triglycerides - not all cholesterol.

Complex issue: Fish oil has multiple health effects beyond cholesterol. Severe hypertriglyceridemia is treated with 4 fish oil tablets a day, can lower triglyceride and raise HDL somewhat. Plant sources of omega-3 need to be converted to the active form which is found in fish oil. In general the worse ones diet is, the more important fish oil is. 1 to 2 tablets of fish oil is reasonable for general health

Based on risk: Statins needed if LDL Cholesterol >190 mg/dL. For LDL chol < 190mg/dL it's based on risk of a heart attack or stroke within 10 years. Treatment suggested if diabetes or if risk is >7.5% (some say >10%) Calculate risk at http://www.mayoclinic.org/diseases-conditions/heart-disease/in-depth/heart-disease-risk/itt-20084942 or http://tools.acc.org/ascvd-risk-estimator/