fresh fish or canned fish? which is better?  

it is better to eat the fresh fish as the y called it 'fresh' mean is still new and the nutrition is still there. Canned fish i called a long time dead fish and this fish did not gives us much nutrition as much as the fresh one. You also can taste the different between the canned and the fresh fish which the fresh fish is much much better taste than the canned fish. As you said that the fresh fish is more safe from the preservatives, can you imagine how long do the canned fish have been prepared before you eat and try to think back how long do the fresh fish will get out of used...then you will say that the fresh fish is much better as it is contain much nutrition and safe to eat also.

Both canned and fresh fish are good. The advantage fo canned fish is that it goes along with fish oil. Fish oil is good for the health and heart. I've read in many medical magazines and studies that fish oil helps in managing blood pressure. As for fresh fish, you're right about avoiding preservatives. Another will be the selection you have for them. In canned fish, sardines, salmon and mackerel are the only choices I know. In our country there are others of the local variety but I really don't know how they are preserved. For fresh fish, I prefer the taste of saltwater fish than fresh water fish. What I know of fresh fish is that there is more calcium you get out of them.