Malaysian trumpet snail (Melanoides tuberculata)

Synonyms: Melania tuberculata, Nerita tuberculata, Thiara tuberculata

Common Names: Red-rimmed melania, red-rim melania, Malayan livebearing snail, Malaysian burrowing snail

Description:

Malaysian trumpet snail (Melanoides tuberculata) is a small freshwater snail from tropical Africa and southern Asia that is sold widely in the aquarium trade [1][2]. When hobbyists dump unwanted tank snails, it can establish in warm waters, breed explosively, and crowd out native snails [1]. MISIN tracks it because a single snail can start a whole population, it can reach enormous numbers, and it can carry parasites that infect people and wildlife [1][2].

Identification:

The Malaysian trumpet snail has a distinctive long, narrow, cone-shaped (trumpet-like) shell that twists to a sharp point, with as many as 10 to 15 turns [1]. Most are about 1 inch (20?27 mm) long, though they can reach up to roughly 3 inches (80 mm) [1]. The shell is light brown and usually marked with rusty reddish spots or flame-like streaks, and the opening can be sealed with a small trapdoor (operculum) [1]. The snails burrow down into soft mud and sand during the day and come out to feed at night, so the churned sediment may be the first sign before you see the snails themselves [1].

They are easiest to find in warm water in the warmer months, on or just under the surface of soft, mucky bottoms in slow streams, springs, ponds, and canals [1]. Because they need warmth, in cold climates they turn up mainly in heated or spring-fed waters and where aquariums have been dumped [1].

At-a-glance cues:

1. Long, narrow, sharply pointed cone-shaped shell with up to 10?15 turns [1]
2. About 1 inch long, light brown with rusty reddish spots or streaks [1]
3. Opening can be closed with a small trapdoor (operculum) [1]
4. Burrows in soft mud and sand by day; active at night [1]

Habitat:

Malaysian trumpet snails live in warm fresh water ? rivers, streams, springs, ponds, ditches, and canals ? and they favor slow or still water with soft, muddy or sandy bottoms they can burrow into [1]. They tolerate a wide range of conditions, including some pollution, but they are limited by cold and cannot survive freezing for long [1]. Because of this, in cool climates they persist mainly in warm springs, heated discharges, and aquarium-fed waters [1].

The snail is native to the warm regions of Africa and southern Asia [1]. In North America it is an introduced species, brought in through the aquarium trade as early as the 1930s and now established in at least 17 states and Puerto Rico, mostly in warm southern and spring-fed waters [1]. In the colder MISIN region it is a watch species, most likely to appear where aquariums or pond plants have been dumped [1].

Reproduction:

The Malaysian trumpet snail is built to spread, and people move it through the aquarium trade. It is dumped from tanks and water gardens, and it hitchhikes on aquarium plants, gravel, and in water moved between tanks or ponds [1]. The most striking thing about it is how it breeds: females can reproduce all on their own, without a mate (a process called parthenogenesis), so the population is often entirely female clones [1]. That means a single snail ? or a few snails on a plant ? is enough to start a new population [1].

Females are livebearers that brood their young inside a pouch and release tiny, fully formed snails, carrying up to about 64 developing young at a time [1]. With no need for a mate and a steady supply of live young, numbers can build explosively, reaching as many as 10,000 snails per square meter in good habitat [1]. The practical lesson is prevention: never dump or move these snails, because once they are in warm water they are nearly impossible to remove (see Management) [1].

Impact and Damage:

Malaysian trumpet snails are not poisonous to touch, but there is an important health note: they serve as an intermediate host for parasites, including the Oriental lung fluke (Paragonimus westermani) and other flukes that can infect people and animals, so the snails should not be eaten raw and hands should be washed after handling them [1][2]. On a property, they can swarm a warm pond or aquarium in huge numbers, which many people find a nuisance [1].

In natural waters, their sheer numbers are the problem. Reaching densities of thousands per square meter, they outcompete native snails for food and space and have caused local die-offs of native snails, and they will even eat the eggs of bottom-spawning fish [1]. They can also pass their parasites to native fish and wildlife [1][2]. Because they breed without mates, tolerate poor conditions, and spread through the aquarium trade, keeping them out of new waters is the only practical defense [1][2].

Similar species:

A few elongate, cone-shelled freshwater snails can be mistaken for the Malaysian trumpet snail.

Quilted melania (Tarebia granifera) is the closest match ? another introduced trumpet-shaped snail in the same family. It is told apart by its strongly sculptured, "quilted" or beaded shell surface and the lack of the rusty reddish spots that mark the Malaysian trumpet snail.

Native river snails (pleurocerid snails such as Elimia species) also have tall, pointed, cone-shaped shells and live in streams. They are generally plainer in color, lack the rusty spotting, and an expert can separate them by shell details ? but a small spired snail in the wild is worth checking against this group.

Monitoring and rapid response:

Signs to watch for:

1. Small, long, pointed cone-shaped brown snails with rusty spots in warm water, on or just under soft muddy bottoms [1]
2. Snails most active at night, burrowing into the sediment by day, often in warm springs or aquarium-fed ponds [1]
3. Very high numbers of small snails building up quickly in a pond or tank [1]

What you can do:

1. Never dump aquarium snails, plants, gravel, or water ? or water-garden contents ? into any pond, stream, or storm drain; rehome them or seal them in a bag for the trash [1].
2. Inspect new aquarium plants and gravel for tiny snails before adding them to a tank or pond, since a single hitchhiker can start a population [1].
3. Do not move snails, water, plants, or bait between waterbodies, and clean, drain, and dry any gear used in the water [1].
4. If you handle the snails, wash your hands afterward and never eat them raw, because they can carry parasites [1][2].
5. Lake associations and crews should monitor warm-water and spring sites, follow clean-drain-dry practices, and coordinate with the state aquatic-invasive-species program, since there is no easy way to remove an established population [1][2].

When to call a professional:

1. A suspected wild population in a spring, pond, or stream ? contact your state aquatic-invasive-species program or local extension office for current guidance [1][2].
2. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. U.S. Geological Survey, Nonindigenous Aquatic Species Database. Red-rim Melania (Melanoides tuberculata) ? Species Profile. nas.er.usgs.gov
2. CABI. Melanoides tuberculata ? Invasive Species Compendium. semanticscholar.org
3. IUCN Invasive Species Specialist Group. Melanoides tuberculata ? Global Invasive Species Database. iucngisd.org

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