Spiked-top apple snail

Native to tropical South and Central America, the spiked-top apple snail is a freshwater species that takes its name from the pointed end of its shell (its ‘spire’), which is high and sharp. The species is also known as the ‘golden mystery snail’.

This species is a popular aquarium snail, often purchased to help keep fish tanks clean. Feral infestations found in Queensland are most likely due to snails being released or escaping into the wild.

Buying and keeping spiked-top apple snails in home aquariums is permitted, provided that they cannot escape into local waterways.

The spiked-top apple snail is not a prohibited or restricted invasive animal under the Biosecurity Act 2014.

Scientific name

Pomacea bridgesii

Other names

  • Golden mystery snail

Description

  • Freshwater snail with shell 40-50mm wide, 45-65mm high.
  • Shell varies from yellow to green and brown, with or without dark spiral bands. Wild form is generally brown.
  • Shell has square shoulders (flat at top of whorls) and almost 90° sutures.
  • Shell aperture (opening) is large and oval; umbilicus (space at centre of whorls on underside) is large and deep.
  • Spire (point on shell) is high and sharp.

Habitat

  • Requires tropical or subtropical environments where winter temperatures do not fall below 10°C.
  • Most of Queensland’s tropical and subtropical freshwater wetlands are likely to be suitable for this species.

Distribution

  • Widely sold and kept in Queensland for use in home aquariums.
  • Small number of naturalised populations have been detected in Longreach and South East Queensland.

Life cycle

  • Life cycle depends on water temperature and availability of food. At high temperatures with abundant food, snail may live for less than 3 months and reproduce at any time of year. When food is scarce, or during drought, can live up to 4 years, with single reproductive period in spring or early summer.
  • Can lay eggs every 15 days, with eggs taking around 3 weeks to hatch. Snails leave water to deposit eggs on vertical surfaces such as vegetation and rocks.
  • Eggs are pale pink to reddish and deposited in distinctive masses above waterline. Individual eggs are 2.2-3.5mm in diameter. Average mass contains 200-600 eggs.

Affected animals

  • native animals

Impacts

  • Although impacts in Queensland cannot be fully predicted, apple snails have proven to be a serious problem wherever they have established, costing large amounts of money to control. They breed rapidly and take over water bodies. They can also carry rat lungworm, which is a parasite that can cause an infection of the brain called eosinophilic meningoencephalitis (meningitis) if they're eaten raw or partially raw.

Environmental

  • Degrades and destroys native aquatic habitat.
  • Competes with native animals for food and space.
  • Affects native species that rely on aquatic plants for food and shelter.
  • Creates potential food sources for predator species, changing predators’ population dynamics.

Social

  • Damages amenity and landscape values of aquatic environments.

Control

  • Early intervention and manual removal of snails and egg masses may suppress numbers.
  • Total eradication is unlikely.

Legal requirements

  • The spiked-top apple snail is not a prohibited or restricted invasive animal under the Biosecurity Act 2014. However, by law, everyone has a general biosecurity obligation (GBO) to take reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control.
  • Local governments must have a biosecurity plan that covers invasive plants and animals in their area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.
  • It is considered a non-indigenous species and it is an offence to release or cause them to be released into the wild.

Further information