When a fish is hungry, there's no stopping it! I landed a big brown trout a few years ago from a tributary of the Huon, with a whole rainbow trout stuffed down its gullet:
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That's admittedly a pretty big brownie - but that's also a 1.2lb rainbow (top left). What's more, the brownie had taken my lure - a 4cm soft plastic - despite having the other fish stuck in its gob! I've no idea how it even saw the lure, let alone got it into its mouth!
(and P S: yes, the brownie went back to the river in good nick)