Eicosapentaenoic acid (EPA) is a type of omega-3 that is essential for healthy immune function, cardiac function, mood, joint, eye, and brain health. Docosahexaenoic acid is also an omega-3 fatty acid. DHA is crucial for neurological and visual development in the human fetus and newborn, and is found in high concentration in the brain. EPA fish oil and DHA fish oil are only found in seafood and marine algae.