Fish (Books)

Mackerel
Mackerel are mentioned in the first book when describing the smell of dragons. The Dragon Nursery is described as smelling of "the stench of dragon - a salty stink of seaweed and old mackerel heads", in Book 1.

Piranha
Piranha are mentioned when Gobber describes what will happen if the Viking Novices wake up the dragons hibernating in the Dragon Nursery. "Dragons this size are normally fairly harmless to man, but in these numbers they will set upon you like piranhas. There'd be nothing left of even a fatso like you, Wartihog - just a pile of bones and your helmet."

- Gobber