Salmon is considered to be a white-fleshed fish, however the meat is pink because of the fact that they absorb the dye from the crustaceans that they eat. Even though salmon may be white on the outside, you will find that it is a nice pink color on the inside because of all the crustaceans that these fish eat.
There are a few different varieties of salmon, though for the most part they all have the same pink colored meat. The white flesh does vary depending on the type of salmon, though most of them are white on the outside. The pink color that the meat has is perfectly normal and is in no way an indication of spoiling or a bacterial infection.