5 Fish You DON’T Want to Catch!

With Invasive Non-Native Species Week (16th-22nd May 2022) now upon us, we take a look at some of the most concerning fish that could turn up in your landing net…

As anglers, we love to catch fish of all shapes and sizes. Right? To many of us, variety is one of the most appealing qualities of freshwater fishing in the UK. With every dip on the float or thump on the rod tip, we all have the chance to encounter something new and exciting. Be it a particularly fine specimen, new species, or even named fish, we’re still in a position to boast some excellent angling opportunities in this country; even with the constant and growing range of pressures our waters face.

Indeed, many of the fish we love to catch are classed as ‘non-native’ – meaning they were introduced from abroad. Fish such as rainbow trout, ide, grass carp and others can be found in managed fisheries around the country, where thanks to a robust permitting system administered by the Environment Agency, they can thrive without impacting native fish stocks. The problem, however, comes with the arrival of new, or more damaging, invasive non-native fish to our shores; each of which threatens angling and the freshwater environment in their own unique ways.

Why should we be concerned?

Like other Invasive Non-Native Species, the fish below all have the potential to directly impact on angling in the UK. If they became established in a water, they could quickly spread; outcompeting, predating on, interbreeding with, and spreading disease or parasites amongst the native fish we know and love. Although the Environment Agency continue to undertake detailed screening of diseases during investigations of non-native species to better understand the risk they pose, it remains our best interests to keep an eye out for these fish, and do everything we can to prevent them taking hold. When it comes to invasive non-native species, prevention is definitely better than cure!

What should I do if I catch one of these fish?

If you believe you’ve caught one of these fish from a river of freshwater venue, call the Environment Agency incident hotline on 0800 807060. Record the location and take the best quality, close up pictures that you can. By recording your sighting and notifying the Environment Agency in this way, you can help inform the management practices that go towards removing these invasive species. Some also have specific further guidance on what to do if caught, which should be referred to below.


1. Prussian Carp (Carassius gibelio)

Adapted from Environment Agency briefing note

With looks similar to a small common carp, brown goldfish or F1, Prussian carp (also known as Gibel carp or carassio) are a fish already widespread across Europe and Asia, with populations now present in the UK. Thanks to their hardy nature and omnivorous habits, Prussian Carp can rapidly colonise new waters, making them highly invasive outside of their natural range. In addition to the threat from their ability to outcompete other fish, Prussian Carp are also of particular concern to our native Crucians – which they can easily hybridise with.  

Read more about Prussian carp, including ID and reporting

Read more about Crucians and the threats they face

2. Pink Salmon (Onchorhyncus gorbuscha)

Pink salmon (also known as humpback salmon) are a migratory salmonid species originating from the Northern Pacific. Initially stocked into European rivers by Russia in the late 1950s to try and develop a net fishery, Pink salmon have since become established in several countries outside their natural range. They are now occasionally caught on UK rivers, which presents a serious concern in light of collapsing native Atlantic salmon stocks. With any number of possible impacts, it’s vital that we better understand the risks they present – and so the Environment Agency asks for any sightings or captures to be reported as soon as possible.

Click here for a detailed ID guide and factsheet about what to do if you catch a Pink Salmon

3. Round Goby (Neogobius melanostomus)

Image: Markus Lundgren

Looking like a kind of bullhead on steroids, round gobies are a Ponto-Caspian species that originate in Eastern Europe, having now been transported outside their native range by ballast water in ships. Already spreading as far West as the Netherlands, these gobies have been identified in horizon scanning work by Professor Helen Roy of the as one of the invasive species that presents the greatest threat to biodiversity, human health and the economy if they were to become established. They have not yet been recorded in the UK, but are definitely one to look out for.

Read more about Round gobies and view a full ID guide

4. Lionfish (Pterois volitans)

Image: Merrit Thomas, Unsplash

Although Lionfish are a saltwater species most associated with warmer climates, they are well worth drawing attention to after a specimen was caught on Chesil Beach in 2021. With venomous spines and a ravenous appetite, Lionfish have become an invasive species across large parts of the world including the Mediterranean, where populations have now exploded. Tolerant of a fairly wide range of temperatures, it’s not impossible that this fish could reach our shores in greater numbers.

If you catch one, contact marinecoordinator@anglingtrust.net

Read more about Lionfish

5. Topmouth Gudgeon (Pseudorasbora parva)

Adapted from Environment Agency factsheet

Despite a shared name, there is little similarity between Topmouths and our native gudgeon, with the invasive Topmouth gudgeon having a very distinctive upturned lower jaw. They originate from Asia and can breed rapidly, causing all kinds of problems for fisheries in the UK. Thankfully though, the Environment Agency are currently undertaking an intensive eradication program to remove this fish from the small number of waters where it has established.

Read more about Topmouth gudgeon and view a full ID guide


Aside from reporting these fish, what else can I do to help?

Always practice good biosecurity, and spread the word!

Thoroughly checking, cleaning and drying and your gear after a session costs nothing, but could prevent all kinds of damaging Invasive Non-Native Species, diseases and parasites from being transferred between waters. It’s something every angler has a duty to follow – and by educating others about the importance of Check Clean Dry, even more of us can do our bit to safeguard fisheries for future generations.  

Consider more advanced biosecurity options through the Angling Improvement Fund

If you’re involved in running a club or fishery, why not consider installing a washdown station? The Angling Improvement Fund (AIF) is currently open for applications around managing Invasive Non Native Species, so funding can be made available for a variety of projects until 6th July 2022. To find out more, visit the AIF landing page on the Angling Trust website, or watch the video below.

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