The waterfalls

These are the two waterfalls connecting the successive pools. The waterfall between the lower and middle pools is just a smooth rock with a gentle slope, and the pools are close together in level. Sometimes the whole school of fish decides to have a contest and see who can jump the highest up the rock, and sometimes someone manages to get into the middle pool and stays there for a couple of days. The area separating the middle and upper pools is a long basically flat rock surface with some indentations ending in an inch high waterfall. When I first got my fish last year about this time I put them all in the upper pool, for some reason. They were tiny little fry back then, and as the summer wore on they all eventually went across the flat area and over the two waterfalls and ended up in the lower pool. But nobody ever made the reverse trip - UNTIL NOW!