Sustainability : Microplastic-Eating Robot Fish Takes To The Water

A prototype of an award-winning robotic fish design that fish filters water to trap microplastics has now been tested in lakes as well as the lab.

Gilbert Wins 

Eleanor Mackintosh’s design for the glow-in-the-dark, water-filtering ‘Robo-fish’ named “Gilbert” won the University of Surrey’s public competition, the Natural Robotics Contest, which resulted in Gilbert being turned into fully 3-D printed working prototype.

How The Robo-Fish Works 

The robo-fish has been designed to work in the following way:

– The watertight tail contains electric motors to power the fins that move the unit around. The head is designed to flood, and the gills either side contain a fine mesh that can filter two-millimetre (microplastic) particles out of the water.

– While swimming, the mouth opens (gills closed) as wide as possible.

– The mouth cavity fills with water, the mouth closes, and the gills open as the floor of cavity is compressed to force water over gills.

– The mesh catches microplastics and the water is ejected.

Other Advantages of The Robo-Fish Design 

It was decided that the robo-fish should only use affordable off-the-shelf components and manufacturing techniques, so that the design is accessible to all. With this in mind, some of the other advantages of the robo-fish design are:

– It can be entirely 3D printed in ABS plastic (dipped in acetone to seal it) with a low-cost fused deposition manufacturing (FDM) printer.

– The modular design i.e., a sealed ‘tail’ unit, onto which the ‘head’ of the robot is attached via a snap-fit joint means that the head can be changed to be updated and meet different gill arrangements in the future.


A prototype of Gilbert the motor-driven, currently remote controlled robo-fish has been tested in an outdoor lake in Guildford (UK) and has demonstrated effective swimming and steering on the water surface.

However, although the prototype, which was developed from a simple sketched idea from the designer can currently swim, ingest, and retain particulates, it cannot yet distinguish between organic matter that is vital to the ecosystem such as plankton and ‘marine snow,’ and harmful synthetic pollutants /microplastics. More development is needed, therefore, to enable the robo-fish idea to work as an effective tool for ocean clean-up and sampling. Also, the developers have suggested that the finished working robo-fish should be automated rather than remote controlled (as it is currently).

What Does This Mean For Your Organisation? 

Although the robo-fish was developed from a simple sketch idea in the first iteration of a contest and needs more work to enable it to be effective, it demonstrates that there could potentially be many different ways to use technology help tackle the microplastic pollution crisis. In reality, the number of robo-fish needed to make even a dent in the level of microplastic pollution wouldn’t be feasible but some good could come from focusing thinking of developing effective filtration systems of biological solutions such as algae that can break down plastics. The fight is now on to find ways that different technologies can be combined to develop multiple solutions to tackle the existing problem, but real progress will be made when the use of non-biodegradable plastics is finally halted and replaced with a better solution for the environment.