ZOOLOGISTS have conducted a detailed mathematical investigation into whether any two goldfish swim in exactly the same way.
The international team, drawn from three cities across the US and France, filmed five fish swimming under standard conditions. They then used six mathematical parameters to define their swimming style, including 鈥淟empel-Ziv complexity鈥� which highlights irregularity in velocity, and 鈥渃haracteristic fractal dimension鈥�, a measure of the fish鈥檚 deviation from a straight line.
Their conclusion, which will come as a relief to pet owners who have started to wonder whether their fish have any personality at all, is that each is a paragon of individuality, cruising the tank in its own unmistakable style. The researchers even go so far as to conclude that the swimming styles of individual fish differ by some 99 per cent (The Journal of Experimental Biology, vol 207, p 697).
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Team member Heike Neumeister at Yeshiva University in New York says the research could lead to a method for detecting water pollution. Even low levels of chemicals cause the fish to alter their swimming style, she says. Hopefully the technique will raise the alarm before the fish are found floating around on the surface.