She is /not/ a subspecies. It's clear in the description (of the image) that she is part of a completely different species. The name is Frost Breath and, as much as the Night Furies and Skrills, it is in the Strike Class.
She does look like Tooth/Night Furies, but it's more because I made her design based on a Siamese Cat (and Night Furies were based on Black Pantheras, also a feline).
Please, don't put your headcanon over my OC. She never was and never will be an "Artic Fury". She is, indeed, a dragon that can be found in places where cold weather predomines. But she has her own species. (Honestly, this is pretty offensive, calling her a subspecie because of your own headcanon.)