My reply was serious " all fish" are predatory to a degree.
If you have a fish tank or pond what happens to a dead fish thats left in? What happens in a tropical tank if any of the live bearers ie guppies have young? They get eaten. I dont suggest for a moment we target all fish with live or dead bait, but it could well be an under used method. I have a feeling that small dead baits may well take some carp waters apart if fished correctly. If there arent already a few anglers already doing so. Take chub, again they can be suckers for a dead bait as can barbel.
If a food source is available in sufficent quantity then it will be exploited.
Chub love chunks of mackerel and I know of a few occasions when Carp have taken deadbaits so I think as has been mentioned, most fish are predatory. I've used live roach for Perch and had them taken by Chub. Pike also like worms too, I've hooked many fishing the Derwent while targeting Perch. I suppose if they are hungry enough, fish will eat anything that's in front of them. 
I think everyone knows of the predatory instincts of Esox, Zeds, Perch and Chub. But if you fish deadbaits at Grafton Mere in Yorks, whilst waiting for a 'Cat' to take your bait you'll get plenty of runs from Carp. Also Loch Maben in Scotland used to be fished regularly with a black Mepps for the big Bream. As Esox20 says All fish are predatory, just some to a greater degree than others.
Thanks for your support roppa and from the few others. I was suprised that what appear to be experienced anglers dont believe this fact. Even as far back as the 50's there were reports coming from Holland of bream caught on live bait. The source of this information was the late Dick Walker.