I didn't see anything regarding the difference between red and pink
What species of salmon are canned? Why is Red Sockeye salmon more expensive than Pink, Chum and Coho Salmon? What are the differences between them? Pink and Chum Salmon are available in greater numbers than Red Sockeye or Coho salmon, making them lesser in cost. Red Sockeye salmon is known for its deeper red color, firmer texture, and higher oil content. Coho or Silver salmon may also be known as Medium Red salmon. It is a softer texture than Red salmon and has a light medium red color. Pink Salmon is more delicately flavored and lighter in color. Chum salmon, also known as Keta salmon, is also lighter in color but usually has a firmer texture than Pink. All species are considered healthy sources of nutrition, such as Omega-3 fatty acids, and may be used interchangeably in most recipes. Some consumers may prefer one specie over the others, depending on taste preferences.
Also taken from net:- They're two different species - "red" salmon, also known as sockeye, are Oncorhyncus nerka; pink salmon, also known as "humpback" or "humpies" due to the rather odd looking humped back characteristic of spawning males, are Oncorhyncus gorbuscha. I think the consensus is that of the two, reds are a better food fish. The other common Pacific salmon species are kings (Chinook) and coho (silvers), both of which seem to get better reviews than reds and pinks, and dog salmon (cohos), which seem to be at the bottom of everyone's list.