An ant is heavier than water. On its own it would sink, and the only reason a real one rides at the surface at all is a thin skin of trapped air that fails the moment the insect struggles, gets rained on, or slips under a riffle. Yet we tie them to float high and dry like a little hopper, when the natural they’re imitating sits down in the surface film, half-drowned and flush.

The thesis is simple: an ant imitation in the sizes that matter, roughly 12 through 20, should float the way a drowning or spent natural does, not high and proud like a hackled dry or a foam terrestrial. Body material, hackle treatment, and profile are the three things that decide whether your fly sits right.