This article published by Science Daily explains two studies performed at NYU-poly on how underwater robots influence swimming patterns in fish. The researchers designed two robotic fish resembling golden shiners. One robotic fish was painted with the natural colors of the golden shiner wile the other was painted with colors not seen in the species. Each robot remained sill, but the researchers used different tail-beat frequencies. The results showed that when a live fish noticed the robotic fish of the same natural color and with the same mean tail-beat frequencies, that fish would spend the longest time with the robot even swimming behind it to gain “hydrodynamic advantage.” The dominant factor, however, turned out to be the coloration of the robot. Even if the robotic fish was using a tail-beat frequency slightly more or less than that of the mean, the shiners were most attracted to the natural color.
The researchers then placed a naturally-colored robotic fish resembling a zebrafish in a tank with zebrafish, experimenting with the robotic fish swimming in circles and still with different tail-beat frequencies. The live zebrafish remained distant from the robotic fish when it was swimming in circles; however, when the robot was still, the live zebrafish swam more closely to each other and matched the robot’s tail-beat frequency even as it increased.
The conclusion of this study is that the flow cues of the tail-beat frequency and the visual stimulus influence the collective response of the schooling fish.
— Alex Lewis