All correct except your use of the term co-dominant. It is a simple dominant gene. Co or incomplete dominance is displayed if a homozygous animal looks different than a heterozygous animnal, which is not the case with this mutation. It is commonly thought of as a codominant gene because of the term "super" given to homozygous salmons, but it was given wrong and early on in the morph game that it has kinda stuck.