Get Regular Updates!
|Robot vs Alien: the freshwater fish saga



Getty Images

Robot vs Alien: the freshwater fish saga

Robot vs Alien: the freshwater fish saga

How do you get rid of an invasive fish that is taking over waterways across the globe? With robot predators designed to scare them, of course!

Robot vs Alien: the freshwater fish saga

Mosquitofish. They are small, pretty, perfect for aquaria – and they’re an invasive alien species in Australia. Just like the cane toad, they were introduced to eat pesky insects, and instead they tried to take over the natural wildlife through competition and predation.

Australia isn’t unique in its story. In fact, mosquitofish are so amazing at invading ecosystems that they have been listed in the world’s 100 worst invasive alien species by the IUCN.

How to fight an alien invasion

Dr Giovanni Polverino from UWA and collaborators at New York University, Professor Maurizio Porfiri and his lab, are working to understand these alien species and how we could possibly combat them.

“It doesn’t matter where you put it, this animal can make it and survive, and adjust to the new environmental conditions,” says Giovanni.

View Larger
Image|Getty images
It may not look like much, but this inch-long invader causes a world of trouble for native ecosystems.

“It’s incredible, they naturally occur in freshwater, but they can also thrive in salt water where very few freshwater species can survive.”

They are also very tolerant to different temperatures, and their eggs hatch inside their parent. ‘Giving birth’ to live young is unusual in fish – and it making them stronger and less susceptible to predation as eggs.

You have to give it to them, they are a pretty amazing species, able to survive just about anywhere. But with this comes huge impacts on biodiversity as they compete with native species.

“Humans have a strong impact on the world, and the spread of invasive species is our fault. They are animals that have been introduced by humans, into places where they don’t belong.”

“And the thing is, if we don’t reverse or attenuate the issue, things are not going to get better.”

View Larger
Image|Atlas of Living Australia
Originally introduced to try to control mosquito populations, the mosquitofish is now found all over the continent.

Here in Western Australia, mosquitofish have been moving into areas of high biodiversity with unique species. Giovanni believes it is important to do something about this invasion before it is too late, and we lose important native species.

“If they are lost here, we can’t just go somewhere else in the world and bring them back.”

So what can we do?

Mosquitofish do have a natural predator, the largemouth bass – another fish on the worst invasive alien species list. Hopefully we’ve learnt enough from the cane toad story not to try and release another predator.

Chemicals like fish toxicants, or trapping them need lots of human time and effort to make it successful, and it can also have a detrimental effect on the native species.

So could scaring it into submission work instead?

Porfiri’s team at New York University has been working with Giovanni to create a robot that looks, and moves like the largemouth bass, which could scare the mosquitofish so much that it changes its behaviour.

A robotic Largemouth Bass
When the robot is around, it scares the mosquitofish. The fish uses up energy trying to protect itself, and seems to have less success reproducing.

Just like any other scientific experiment, the robot fish has evolved over time.

“We had no idea how to make a robot interact with live fish, so we started very, very basic, with something that looked like a fish, that we thought was moving like a fish – but that was with our eyes not with the eye of a fish!” Giovanni says.

They had to understand what the fish liked, didn’t like, and work on the robot until it became an effective robot predator.

So just how does the robot work?

“The robot alters the behaviour of the fish, but also the fish has an influence on the robot – they do interact with each other in real time. When the fish is close to the robot, the robot will attack and the fish will swim away. We are studying the mathematics of this interaction to understand the underlying relationship.”

The team found that just 15 minutes of exposure to the robot largemouth bass per week had longer term effects on energy levels and body condition. The mathematical models also helped the team to understand the movement patterns that the robot should take to scare the invasive mosquitofish the most.

View Larger
Image|Giovanni Polverino
Right now the robot fish are tested in tanks – but the team hopes to test them in real environments soon.

At the moment, these studies have been within tanks in controlled environments. Before the robots head out to help fight the aliens, there are a few more questions that need to be answered.

What are the long term impacts of the robot on the mosquitofish? How many of these predator robots are needed, and could they also affect the native species?

Giovanni and the team are working on finding answers already – and before we know it, robot fish could be part of helping humans reverse our mistakes. Aliens versus robots: the saga continues – and we know which one we’d rather win.

Particle Puns


Creative Commons Logo

Republishing our content

We want our stories to be shared and seen by as many people as possible.

Therefore, unless it says otherwise, copyright on the stories on Particle belongs to Scitech and they are published under a Creative Commons Attribution-NoDerivatives 4.0 International License.

This allows you to republish our articles online or in print for free. You just need to credit us and link to us, and you can’t edit our material or sell it separately.

Using the ‘republish’ button on our website is the easiest way to meet our guidelines.


You cannot edit the article.

When republishing, you have to credit our authors, ideally in the byline. You have to credit Particle with a link back to the original publication on Particle.

If you’re republishing online, you must use our pageview counter, link to us and include links from our story. Our page view counter is a small pixel-ping (invisible to the eye) that allows us to know when our content is republished. It’s a condition of our guidelines that you include our counter. If you use the ‘republish’ then you’ll capture our page counter.

If you’re republishing in print, please email us to let us so we know about it (we get very proud to see our work republished) and you must include the Particle logo next to the credits. Download logo here.

If you wish to republish all our stories, please contact us directly to discuss this opportunity.


Most of the images used on Particle are copyright of the photographer who made them.

It is your responsibility to confirm that you’re licensed to republish images in our articles.


All Particle videos can be accessed through YouTube under the Standard YouTube Licence.

The Standard YouTube licence

  1. This licence is ‘All Rights Reserved’, granting provisions for YouTube to display the content, and YouTube’s visitors to stream the content. This means that the content may be streamed from YouTube but specifically forbids downloading, adaptation, and redistribution, except where otherwise licensed. When uploading your content to YouTube it will automatically use the Standard YouTube licence. You can check this by clicking on Advanced Settings and looking at the dropdown box ‘License and rights ownership’.
  2. When a user is uploading a video he has license options that he can choose from. The first option is “standard YouTube License” which means that you grant the broadcasting rights to YouTube. This essentially means that your video can only be accessed from YouTube for watching purpose and cannot be reproduced or distributed in any other form without your consent.


For more information about using our content, email us:

Copy this HTML into your CMS
Press Ctrl+C to copy

We've got chemistry. Want something physical?