Red imported fire ant

Page last updated: Monday, 30 May 2022 - 12:22pm

Please note: This content may be out of date and is currently under review.

The Department of Primary Industries and Regional Development detected red imported fire ant (Solenopsis invicta) at two adjoining tenanted properties at Fremantle Ports in November 2019. An eradication program is in the final stages of completion.

If red imported fire ant (RIFA) became established in WA, it could severely damage the local environment, economy and Australia's outdoor lifestyle. RIFA inflict a painful, fiery sting, which in rare cases can cause an acute allergic reaction.

Eradication activities

The department's six rounds of RIFA surveillance and treatment have been successfully completed with no further detections of this invasive pest. The program is now in the final stages of proving WA is free from RIFA.

Fremantle residents, local government, businesses and Fremantle Ports and their tenants have been incredibly supportive and cooperative with surveillance, baiting and quarantine activities. This has been crucial to the department’s successful response to this invasive ant incursion, and the department needs this support to continue.

As of 1 December 2021, the Quarantine Area has been lifted.

Quarantine Area

Quarantine Area Notice (QAN) for parts of Fremantle first came into effect on 5 December 2019, and was extended on 29 May 2020, 1 December 2020 and 1 June 2021. The Quarantine Area has now been lifted.

How to identify Red imported fire ant


Many different sized ants can be found in one nest


Red imported fire ant (RIFA), Solenopsis invicta, is one of the most serious and invasive ant pests in the world, because of its harmful effects on people, agriculture, flora and fauna, infrastructure and recreational activities.

Below is information on what to look for. This identification video (courtesy of the National Red Imported Fire Ant Eradication Program) may be useful if you are looking for nests or observing ants.  Although please keep in mind any RIFA nests in WA will look different to nests in Queensland due to our sandy soils.

What to look for

  • Hard to distinguish from common native ants.
  • 2-8mm, reddish brown in colour with a darker abdomen.
  • Ants of varying sizes in one nest.
  • Nests that often have no visible entry holes like other ant nests.
  • Young nests can be indistinct or start out as small piles of excavated soil.
  • A fiery sting that can blister and form pustules at the sting site.

Where to look

RIFA nests may be found next to or under other objects on the ground, such as timber, logs, rocks, pavers or bricks. Look near pots or any areas of disturbed ground as well as:

  • pot plants on the ground
  • stores of topsoil, mulch and potting mixes
  • open areas like lawns, firebreaks or fence lines.
  • under landscape materials (e.g. logs, stones)
  • under timber or pallets on the ground
  • adjacent to buildings and other structures
  • untidy or overgrown areas
  • near areas of permanent water (e.g. the banks of dams, rivers, ponds, aquaculture containers)
  • tufts of grass in open areas, where the soil is built up around the tufts.

Impact of RIFA


  • Can inflict a painful and fiery sting, which in some people can cause an allergic reaction.
  • Fire ants usually move quickly, allowing large numbers to move onto humans before they are detected.
  • Stings from fire ants can cause a painful, burning, itching sensation, lasting up to 1 hour.
  • Multiple stings give sensation that body is on fire.
  • Small pustules may form at sting sites several hours after stinging and may become itchy.
  • Broken pustules may become infected.


  • Can eventually form 'super colonies' with multiple queens and can spread rapidly.
  • Potential to inhabit most of Australia’s major coastal areas and extensive areas of tropical north.
  • Feed voraciously on small ground fauna, including insects, spiders, lizards, frogs, birds and mammals. Could displace or eliminate some native species.
  • Eat and damage seeds, possibly causing major ecosystem changes over time.


  • Fire ant mounds can be serious problem in lawns, sporting fields and golf courses.
  • Damage sensitive electrical equipment.
  • Affect tourism industry and export of items to fire-ant-free countries.
  • Significantly affect agriculture industry. More than 50 agricultural and horticultural crops, as well as turf and nursery species, are affected by fire ants. All are grown in Australia, in areas that fire ants could inhabit.
  • Attack young animals, stinging around eyes, mouth and nose, leading to blindness and suffocation.
  • Prevent animals from reaching food or water without being seriously stung, leading to starvation and dehydration.
  • Can damage and kill some plants by tunnelling through roots and stems.
  • Protect some pest insect species that produce 'honeydew', downgrading quality of produce and helping to spread disease.
  • Feed on important biological control agents, interfering with integrated pest management practices.
  • Mounds can destroy equipment, such as irrigation systems, and damage machinery during harvesting operations.


  • Restrict everyday activities such as picnics and sporting activities as backyards, parks, school playgrounds and sports grounds are unusable.

RIFA safety and first aid advice

Always safety first if you come across an ant nest. Don’t stand on the nest or disturb it as ants may aggressively defend it. Only take photos if safe to do so.You should take the following steps if stung:

  • If the ants are still on you or your pet, pick them off by hand. If you try and brush them off this will make them more aggressive, and if ants are sprayed with water, they may latch on with their jaws.
  • Apply a cold compress to alleviate swelling and pain.
  • Carefully wash the affected area with soap and water.
  • Immediately seek medical attention if you are allergic to insect stings or have symptoms of allergy.

Fire ant stings can take up to 10 days to heal. If the blisters or pustules break, there is a risk they can get infected. If pain persists or blisters get infected, see your doctor. Infected stings may require antibiotics.

Visit HealthyWA for more information.

Frequently Asked Questions 

What is a red imported fire ant (RIFA)?

A red imported fire ant is a serious exotic pest that poses significant social, economic and environmental threats to Western Australia. It is native to South America and is known to be highly aggressive and invasive and can inflict painful stings on people, pets and livestock.

How did it get here?

Results from genetic testing indicate the ant detection in WA was most likely introduced from overseas and is not linked to the Queensland detections. It is possible they arrived on a shipping container or on earth moving machinery and equipment.

Where have they been found?

RIFA were detected during specific targeted surveillance by the Department of Primary Industries and Regional Development (DPIRD) on two adjoining properties at Fremantle Ports. It appears that the detection is localised to the initial detection site. An established red imported fire ant nest was found on the site.

How do I tell if ants are red imported fire ant?

Red imported fire ants are small (2-8mm), reddish-brown in colour, with a darker abdomen. There can be many different sized ants in one nest. They are usually aggressive if disturbed and can inflict a painful, fiery sting. Fire ant nests often look like disturbed soil or a small mound of soil with no visible entry holes. Nests may be in open areas or under logs, rocks or garden materials. 

Where should I look?

Look around any areas of disturbed ground, pot plants, top soil, mulch, under landscaping materials such as logs or stones, in any untidy or overgrown areas, or near areas of permanent water (eg. dams, rivers or ponds).

Why are they a problem?

Fire ants are one of the world's worst invasive ant species. They pose a serious threat to our lifestyle, environment, economy and agriculture, as they can form supercolonies that spread rapidly, feeding on insects, small ground fauna and crops. They also extremely aggressive and cause painful stings, which in some cases may cause anaphylactic allergic reactions. You can read more on their impacts here.

Can I treat an infestation myself?

No. Do not disturb a suspected red imported fire ant nest, as they are often highly aggressive and may swarm if disturbed. If you suspect red imported fire ant contact DPIRD IMMEDIATELY.

What should I do if I get stung?

Refer here for first aid advice. Apply ice to relieve the swelling and pain. Gently wash the area with soap and water and leave any blisters intact. People who experience an allergic reaction after an insect sting should seek medical attention immediately.

What do I do if I suspect red imported fire ant?

LOOK AND REPORT! Report any unfamiliar ants immediately – even if unsure.

Do not disturb ants as they may aggressively defend the nest. Do not send in live ants. Take a photo if safe to do so. 

Contact the department via:

What has been done to control RIFA in WA?

All known RIFA infestations have now been treated with baiting and direct soil injection. Eradication efforts are being undertaken in conjunction with the National Red Imported Fire Ant Eradication Program.

How do RIFA spread?

RIFA can spread naturally through flight, and by assisted spread such as movement of infested materials. Fire ant nests can have a single queen or multiple queens. A new queen will lay up to 20 eggs initially. Eggs hatch in 7-10 days and become adults after 9-15 days. A queen can increase laying capacity up to 800 eggs per day after the initial hatching.

What can I do to help prevent the spread of fire ants?

Report suspected red imported fire ant immediately.