A trout eating a bumble bee is something I had never previously seen. But it happened, right there, before my very eyes.
The bumble bee came into my line of vision, struggling to escape the surface film. I saw a rainbow trout of a pound or so spot it, approach it hesitantly, hang just beneath it and then take it, but without much conviction. A second later, its hesitancy apparently justified, it spat it.
No sooner had it done this than a much bigger fish saw what happened, darted in scattering the smaller fish and took the bee in a big, positive gulp.
Whether it was just territorially asserting itself to the smaller fish, or bumble bee features as a normal part of its diet, or indeed if it is at all common for a bee to end up in the river in the first place I don't know. It was an entertaining diversion though.