What you'll need will vary depending upon the recipe you are using, the cost, and the availability. Water-packed tuna is lower in calories and contains more omega 3's, while oil-packed tuna has more flavor and is usually packed in heart-healthy soybean oil. White Albacore has a firmer texture, light color, mild flavor, and higher mercury levels. Skipjack contains the strongest flavor, highest fat, is light brown in color, with the lowest mercury levels. Yellowfin (or Ahi) has a pale pink color, a mild flavor, and is higher in mercury than skipjack. Tongol contains less mercury and is comparable to Skipjack. For low-sodium, sometimes you can find it in the store, but if not rinse the fish for 3 minutes after draining it to remove a lot of the sodium. If you are pregnant, it's best to choose one with the lowest mercury or the Safe Catch brand.