A crudely-designed zebrafish replica that attracts shoals of
curious fish could be used to guide them away from
The 15cm-long robot fish, built by a team of researchers at the Polytechnic
Institute of New York University and Instituto Superiore di Sanitá
in Italy, was fashioned out of lightweight shape memory alloys
(SMAs), which meant it could adopt a curved, flexible spinal
structure that mimics the continuous movement of a real fish in
These movements attracted both male and female fish during
experiments, the results of which were published in the Bioinspiration
and Biomimetics journal on 8 June. The paper reports "the
mechanisms by which standard swimming patterns can be reproduced",
with the intention of eventually using these methods to create a
robot fish that can protect and monitor ocean populations.
"We want to make sure first that we do have an attraction and
that the fish are conditioned for the attraction," Maurizio
Porfiri, one of the paper's authors, told Future of Tech. "Then we want to integrate those into some
algorithms that we can use for providing intelligence to the robot.
We would like to use these robots for guiding fish away from
The fish replica was placed in a 65-litre fish tank, its tail
controlled mechanically by the researchers. The tank was made up of
one large section with two smaller tanks either side. The team then
conducted 16 different experiments, using the divides in the tank
to see how lone fish and groups of ten reacted to one another and
to the robot fish.
It was discovered that zebrafish given the option between
swimming with real fish and swimming with the robot usually
preferred to be alongside their own kind. However, both male and
female fish opted to swim beside the robot rather than an empty
tank -- lone fish and shoals of fish were both attracted to the
robot fish in these instances.
By separating the fish physically from the robot, the team could
ensure any attraction was not based on the fish merely seeking out
shelter from the rather large robot.
The robot was given a few enhancements to make it more appealing
-- its robust body was rounded like that of a fertile female and
its stripes and colouring were made more vibrant than the real
thing. The team said that the combination of its biological
features and the natural movement of the tail attracted other fish,
though the mechanical noise it made limited this somewhat.
The team is now studying how fish interact with the replica when
swimming alongside it.