Sierra's not a flattooth. He's a sharptooth flyer.
Hmm..favorite hero, probably Chomper. Fav villain, Sharptooth hands down.
Whether or not Sierra is a Sharptooth flyer or not is unknown. Petrie is supposed to be a Shaprtooth flyer too, so we cannot assume, just because Sierra's species eats fish, that he is a Sharptooth flyer.
Actually, if Sierra eats fish, then he is a sharptooth. Fish is meat. If he's confirmed to eat both meat and plants, then...well LBT has no term for that, but halftooth would best describe it. He certainly would not be a flattooth.
As Ducky would say: "Oh no, no, no. That is not what I meant. No it is not."
I said that in real life, both Sierra's kind and Petrie's kind would eat fish. Petrie's kind eats leaves in the films. So, we cannot assume that Sierra eats meat based on what his species eats in real life because of the change in Petrie.
In fact, I read that even Mo and Elsie might be carnivores in real life.
Also, Ichy would, like Petrie in real life, eat fish, so he shouldn't actually be a danger to the Gang of Five, yet he is in film IV.
Also, I use the phrase "Bothtooth" for omnivore, as it makes more sense anyway. Wish LBT would pick it up.
