![Image](http://upload.wikimedia.org/wikipedia/commons/b/b5/Rainbow_trout.png)
I suspect, like everything else on wikipedia, it was ripped off from somewhere.
My theory is that it originates from Asterix the Gaul - and the fishmonger Unhygienix, who was always hitting people with fish.
![Image](http://i648.photobucket.com/albums/uu203/runza/ASTERIX_fisch.jpg)
Yes, OK, nearly off-topic - but we're still talking about wikipedia???