Fish and chips is a factory-made monstrosity: breaded, deep-fried, and drenched in artificial seasonings. You're not eating fish and potatoes, you're consuming a processed, oil-soaked abomination. Just grill your fish and boil your potatoes.
Why trash
The batter is refined flour, deep-fried in industrial seed oil. The chips too. All the omega-3 benefits of the fish are cancelled out.
Try instead
Grilled or baked fish with roasted vegetables.