Since dogs and cats cannot produce omega-3 essential fatty acids, they must be taken as dietary supplements. Fish oil is the best source of omega-3 fatty acids for pets. Ongoing research indicates that they are a beneficial daily dietary supplement for humans, dogs, and cats. Omega-3 fatty acids are used to : - support kidney and heart function; - maintain a healthy skin and coat; - maintain overall health. Omega-3 fatty acids may also support joint health.