Scientists from the Czech Republic and Germany studied how carp arrange themselves in 80 different barrels while waiting to be sold at the traditional Czech Christmas sale last year. They observed fish in 817 samples over seven days. What diid they find?
We found that carps displayed a statistically highly significant spontaneous preference to align their bodies along the North-South axis. In the absence of any other common orientation cues which could explain this directional preference, we attribute the alignment of the fish to the geomagnetic field lines.”
Was the research tough? It was as easy as counting fish in a barrel! Link