I can only go by my experience and Armatus was the easiest and quickest to turn as that just struck food that went in on the surface within a few daysHow long will they stave before eating anything?
Tattuaia took about a week longer and needed it dropped infront of its mouth where it was chiling out and scombs took longer and needed the food floating above it so it could strike it from below
It will take it though I have no doubts armatus are greedy as hell