I have a good reason to eat fish. Once I heard from a report which says that fish is rich in omega-3 fatty acids which are good for women. They can make women at lower risk of developing age-related macular degeneration. So your sister is right. We should eat more fish.
Your sister is right. We should have one or more servings of fish per week. If we do that, we are less likely to develop macular degeneration related to age than those who have less. We can benefit from eating dark-meat fish such as think sardines, salmon, swordfish, bluefish and mackerel. Canned tuna is also a good choice.