true albinos in any animal are rare in the wild, and many people mistake animals that are white with light colored eyes for albinos, but a true albino will have no pigment, AT ALL, and an animal tat is white with red eyes has light colored pigment. (a pink eyed white rat would be an example of this)
the only reason that FW albinos are seen so often is because they are bred for the albino gene over and over and over. do not forget that most albino fish you see are fish that are easily bred (corydoras catfish, cichlids, bristlenose catfish, all very strait forward to breed/ raise).