User blog comment:Ion Eduard Andrei/Dragon clases/@comment-24018437-20140531102818

Actully, a new book called 'Guide to Dragons' confirmed that the Snafflefang and Red Death are Stoker Class Dragons.

The Deadly Nadder was moved to the Tracker Class because it appearntly has an amazing sense of smell. Its unknown why its still symbol of the Sharp Class.

The Brainpicker is a Dragon from the Book, and doesn't exist in the movie universe. Somebody once edited it into the Fear Class, but its considered fake info.

The Hobblegrunt is indeed a Boulder Class Dragon.

The Fear Class has been deleted, and all Fear Class Dragons were moved to the Mystery Class.

All this information is in 'Guide to Dragons' and the new HTTYD-Website.