Paddy gets both sardines and mackerels but I give him the ones in sunflower oil, to up the essential fatty acid intake. He doesn't really like them and really dislikes the ones in tomato sauce but tough luck - he needs to eat them! I also supplement about 4 or 5 days a week with 1000 mg of fish oil (fish body oil, not cod liver oil) plus 100 i.u. capsules of Vitamin E Oil - they work in harmony to maximise absorption and feeding one without the other can cause a deficiency.