Feral Fish

Carp Love 20°C

How to Identify Carp and other feral fish species

- Identifying Eastern Gambusia
- What Small Fish Is That?

Why Target Feral Fish?



Carp Love 20°C

The water is warming - 'Carp Love 20°C' is on again this Spring!


Carp are a major problem in Murray Darling catchment. Knowing more about carp in our catchment is really important! They are one of our worst aquatic pests and can breed up very quickly. Mapping carp hotspots and where they breed is important for understanding their behaviour and identifying opportunities for control. Carp are often thought to require large and warm wetlands to breed, but we have very few of those types of wetlands in the ACT region and we still have lots of carp!

LISTEN, LOOK and LOG to help to fill in the pieces of the carp puzzle!

Anyone can recognise a carp breeding event! LISTEN for the splashing, LOOK for the carp and LOG your sightings at FeralFishScan

'Carp Love 20°C' takes its name from carp's tendency to display breeding behaviour when water temperature reaches around 20°C. The water is warming and Waterwatch would like you to keep an eye out for behaviour such as splashing around the edges of waterways as seen in the Youtube video below and log your sightings on the FeralFishScan website (hosted by the Invasive Animals Cooperative Research Centre). Such information will help us to build a picture of where carp are breeding in the upper Murrumbidgee catchment and to look at more effective measures to control them.

Score yourself a  'Carp Love 20°C' t-shirt!

Capture video footage of carp breeding or gathering in big numbers and share it on the ACT Landcare and Waterwatch Facebook or Twitter sites using the hashtag #carplove20 to score yourself a free 'Carp Love 20°C' t-shirt! Sightings must be of carp in the upper Murrumbidgee catchment (the ACT region including Yass and Cooma areas) during Spring 2019.

Carp t-shirts

How to Identify Carp and other feral fish species

Do you know which fish species you've seen? There are 5 major feral fish species that live in the Upper Murrumbidgee catchment. They are common carp, redfin perch, eastern gambusia, oriental weatherloach, and goldfish. There are also some native species that can be easily mistaken for feral fish. To find out how to identify feral fish, click here.


At the beginning of October 2015, carp have already begun breeding at the downstream end of Sullivan's Creek

This photo was taken at Sullivan's Creek. Carp have been regularly gathering in circles near the surface of the water. No one is really sure why they do this but it believed to be a social exercise rather than a feeding/breeding activity.

Carp Circles_ Sullivan's Creek

This footage taken by Dr Danswell Starrs shows Carp spawning at McKellar Wetlands in Belconnen during October 2015.

Carp are easy to spot when they're spawning as they splash around in shallow water dispersing their eggs throughout the water plants.


Carp at Mckellar Wetlands

Carp eggs taken on the same day at McKellar Wetlands. Eggs are 3mm in diameter and take approximately a week to hatch.

A single, large female can produce up to 1.5 million eggs in a single spawning event!!

Carp eggs

How to Identify Eastern Gambusia

Gambusia ID

What Small Fish Is That?

Identifying small fish in our waterwys is very useful as there are a lot of them and they are commonly encountered by Waterwatchers. They can be, however,

difficult to identify. How do you know if you are looking at a juvenile carp or a adult Australian Smelt? Help is at hand with the presentation below by our resident fish expert Dr Danswell Starrs
What Small Fish Is That?

Why Target Feral Fish?

Since European settlement, the deliberate or accidental introduction of non-native fish into Australian freshwater ecosystems has resulted in the establishment of many populations of pest fish species. These species are broadly considered as 'pests' because they threaten native fish species, river health and aquatic ecosystems by:

  1. Degrading or compounding the degradation of aquatic ecosystems by stirring up sediment, undermining river banks and increasing nutrient levels
  2. Feeding on or destroying native aquatic plants
  3. Competing for native fish food/habitat and preying on native fish or frog eggs
  4. Spreading disease and parasites that can adversely impact native species.
Pests such as European carp (also called Common carp), Redfin perch, Eastern gambusia, Oriental weatherloach and Goldfish are listed as ‘noxious’ in NSW by the NSW Department of Primary Industries, and are listed as a pest species by the ACT Government.
To find out more about what is happening across Australia to control pest fish and protect native fish species, visit the Finterest website.



FeralFishScan is a community website managed by the Invasive Animals Cooperative Research Centre and dedicated to collecting evidence of feral fish in our freshwater rivers. 

Species such as European carp, Redfin perch, Goldfish, Gambusia and Oriental weatherloach are found in many rivers, but exactly where they occur is poorly known. These species are directly impacting on our native fish and aquatic fauna in many ways, including the spread of disease/parasites and predation on the young and eggs of native species.

Some pest fish can also affect the health of our rivers, lakes and creeks by compounding the effects of degradation from other sources, which in turn can affect the ability for native fish and aquatic fauna to thrive and breed.

Although we know roughly how these species are impacting our rivers, lakes and creek systems, we don’t have detailed catchment-wide data on where these pest fish are found or their numbers. We need your help to address this knowledge gap to better manage the effects of pest fish throughout our wonderful catchment.

You can help by recording sightings of pest fish in the FeralFishScan community mapping facility throughout your catchment area. This data will then be available for everyone to see and use.

FeralFishScan Website



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