Omega-3 fatty acids are the single most cited reason for eating fish. Understanding which fish deliver them, and how much, transforms your food choices.
## The three omega-3s that matter
**EPA (eicosapentaenoic acid)** - cardiovascular and anti-inflammatory benefits.
**DHA (docosahexaenoic acid)** - brain, retinal, and nervous system development.
**ALA (alpha-linolenic acid)** - plant-based; conversion to EPA/DHA in humans is limited (<10%).
## Top fish by omega-3 content
Per 100g cooked serving:
- Atlantic salmon (farmed): 2.3g EPA+DHA
- Sardines: 1.5g
- Mackerel: 1.3g
- Herring: 1.5g
- Anchovies: 1.5g
- Rainbow trout: 1.0g
- Bluefin tuna: 1.3g
- Halibut: 0.5g
- Cod: 0.3g
## Wild vs. farmed and omega-3s
Farmed salmon actually contains MORE total omega-3s than wild - but the ratio of omega-3 to omega-6 is often worse due to grain-based feeds. The best oily fish sources balance both metrics.
## Supplements vs. fish
Fish-oil capsules deliver comparable EPA+DHA at lower cost, but multiple studies show whole-fish consumption outperforms capsules on cardiovascular outcomes - possibly due to synergistic proteins, selenium, and vitamin D that only whole fish provides.
## Building a weekly rotation
Two servings of oily fish per week is the widely-cited target from major health organisations. Rotate between salmon, sardines, and mackerel to vary mercury exposure and support different fisheries.