Salmons are bad for your health.

Salmon flesh is generally orange to red, although there are some examples of white fleshed wild salmon. The natural colour of salmon results from carotenoid pigments, largely astaxanthin but also canthaxanthin, in the flesh. Wild salmon get these carotenoids from eating krill and other tiny shellfish. Because consumers have shown a reluctance to purchase white-fleshed salmon, astaxanthin (E161j), and very minutely canthaxanthin (E161g), are added as artificial colorants to the feed of farmed salmon, because prepared diets do not naturally contain these pigments.

Research has revealed canthaxanthin may have negative effects on the human eye, accumulating in the retina at high levels of consumption.

What I'm trying to say is that the salmons sold in Singapore are mostly farm bred and farm bred salmons are white-fleshed because of the lack of krill and other tiny shellfish to feed on in farms. Ergo, large amount of salmons may cause your eyesight to deteriorate, rather than benefiting your eyesight as the consumption of fishes would otherwise promote.