I currently have three swimming respirometers at my disposal, which I can run at the same time. The upper video is showing the setup.
Perch (yellow perch and European perch) are said to be poor swimmers, but I decided to give them a go anyway. The lower video shows a 14 g yellow perch at 22 ºC at a velocity of 3.5 body lenghts per second (42 cm per second). I would say that it is not too bad a swimmer after all: It almost swam 1 body lenghts per second faster than this before it gave up (30 min periods, 0.5 body lenghts per second increments). The lighting was kept dim to stress the fish minimally, and I put some of the plastic water plants I keep in their holding tanks on top of the tunnel for shelter.