Well, there are two things unusual about this variety of canary.
This particular bird belongs to the red factor canary strain.
Red factor canaries did not appear from a mutation within the canary species. That color does not exist in the normal canary genome.
Instead, this color came about through hybridization with the black-hooded red siskin from South America. The fertility of the canary/black-hooded red siskin hybrids was not very good, but a few were fertile and were bred back into the canaries.
The red coloration that comes from the black-hooded red siskin requires a diet rich in carotenoids. The flamingo requires exactly the same sort of diet to maintain their pink plumage.
At one time, canary association would not allow this color because of the long standing rule that no show canary should be fed an unnatural diet.
But now it is a popular color-bred bird and, for some reason, always available at Petco.
