Vit D3 sources from fish From wikipedia  Feb 2010
Natural sources of vitamin D include:[2]
    * Fish liver oils, such as cod liver oil, 1 Tbs. (15 ml) provides 1,360 IU (one IU equals 25 ng)
    * Fatty fish species, such as:
          o Herring, 85 g (3 ounces (oz)) provides 1383 IU
          o Catfish, 85 g (3 oz) provides 425 IU
          o Salmon, cooked, 100 g (3.5 oz]) provides 360 IU
          o Mackerel, cooked, 100 g (3.5 oz]), 345 IU
          o Sardines, canned in oil, drained, 50 g (1.75 oz), 250 IU
          o Tuna, canned in oil, 85 g (3 oz), 200 IU
          o Eel, cooked, 100 g (3.5 oz), 200 IU
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Also – apparently salmon liver oil has 2X the vitamin D than does cod liver oil