Heart failure (HF) incidence increases worldwide and is affected by various risk factors such as coronary artery disease, hypertension, obesity, and diabetes. Dietary recommendations for patients with HF have generally focused on sodium restriction; however, different nutritional approaches are considered in patients with a high risk of malnutrition due to the diuretic drugs they use. Omega-3 fatty acids obtained from aquatic organisms are essential regulators of cardiovascular health. There are different opinions on giving/consuming omega-3 fatty acids (and supplements) to improve the symptoms of heart failure. Although found mainly in oily fish, EPA and DHA, the marine n-3 polyunsaturated fatty acids are now found in commercially available supplements over the counter (as fish oils) or as concentrated pharmaceutical preparations. Fatty fish is the premier natural food source of EPA and DHA. In this study, we review the effects of omega-3 fatty acids, associated with low cardiovascular disease risk, on HF while trying to understand if it could ameliorate or exacerbate HF.