I have a question about the bluefin:
(I understand this is all fantasy but I'm trying to figure something out logically)
If it hunts on thin ice primarily would it not have larger hooves?
Physically all it's wieght would be placed on the four smaller hooves, which would crack the ice more easily while larger hooves would spread the wieght over a larger area and not put as much stress on the ice, much the same way with camels and how they walk over sandy areas much more easily than a horse.
They're still awesome though