Stage 2 · The Fish
Getting refused is the useful part.
The bait you built in the Tank, shown to a real predator under real conditions. It runs the actual predation sequence — detect, approach, track, commit — and any stage can fail. When it does, you get the reason, not a shrug.
Verdict
Three models stacked: lure physics from the Tank, visibility from the Fish Vision Camera, and a behavioural model on top. Every number it uses is onthe model page, including what it cannot represent — motion, scent, sound above the lateral-line band, and the fact that fish are individuals.