Theoretically fish oil is rich in omega-3 fatty acids, and the omega-3 fatty acids can help moisturize the ocular surface, decrease dryness and whiten eyes over time. And there is a positive relationship found between taking omega-3 fatty acids and dry eyes disease improvement. So i think that there may be other reasons that your eyes get red. Because red eyes are often a sign of dry eye syndrome, so i think that maybe you get eye syndrome and the fish oil you take in is not enough to prevent it.
Yes, sometimes fish oil can cause red eyes. Because it has been searched that the increasing omega 3 intake can make blood vessels more susceptible to bursting and fish oil is rich in omega 3. So you need to intake less fish oil and increase the intake of Vitamin C, which can strengthen the walls of the blood vessels. Also, red eyes can be caused by coughing, sneezing, or accidentally punching yourself.
Yes, the fish oil is good for eyes because of moisture role. However some people's physical character belongs to the sensitive one. That is why you get red eyes when you take some fish oil because of the stimulation. You need to use the warm compress by finding the hot water and clean cloth to release the symptom which will be so workable.