Fish oil is not essential. Fish get their omega 3 from plants. It is difficult to be deficient in Omega 3 if eating 1-2 tablespoons of flax seed meal or chia seeds and green leafy vegetables at several meals. There is also research that suggests that those on plant based nutrition become highly efficient in their own manufacture of omega 3. Patients on fish oil are also at increased risk for bleeding, and studies now indicate they are of no benefit for heart disease patients.