I have already posted a salmon patty recipe, so I thought I would move on to tuna. I buy Ahi tuna, which is most commonly used in raw Japanese fish dishes such as sashimi. Ahi refers to two species, bigeye tuna and yellowfin tuna. With yellowfin being most common, it has nice red pigmentation to skin, it is more perishable than bigeye and looses its red pigmentation quicker. So when buying look for a good bright red colour for freshness.