Oily fish is defined as fish with a proportion of fat higher than 5-6% of their muscle mass: sardines, longfin tuna, mackerel and horse mackerel are some the most well known examples. Oily fish ...

You can find canned longfin tuna (albacore), yellowfin tuna, skipjack tuna and bigeye tuna, among other kinds. High-end canned tuna is often longfin tuna, which is characteristically whitish in color.