I believe that their entire line of foods have the same basic ingredients in them. The main differences between them being that the protein/fat content varies slightly as well as the order of some of the lesser ingredients. The Thera A+ line has garlic added to it to boost immune systems and the Finiky Fish formula has mussels added to it. So for the most part, they are very similar.
I think the main differences between the line is the form (pellet, floating, sinking, wafer, flake, etc.) and size so pick whats best for your fish and you're golden. My fish love NLS.