Lemon juice is the answer. I pour that on the tuna and it pretty much kills the smell.
Pintoca, I see what you are saying and thank you for the response. My big thing is that I eat more carbs that I need and I need to up my protein intake without adding many more calories and tuna seems the best way to do that. I don't like vegies, so if I juice them, I can get some of the benefit from them anyhow. I know that I can't spot reduce, but I need to lose some fat or avoid putting much more on for right now. Once I start to lose fat, my mid section will start to melt away fairly quick on me. That's the only place I gain it. My arms and legs have virtually no fat on them.