Malaysian trumpet snails are one of the hardest aquarium pests to eliminate. They burrow into substrate during the day, reproduce without mating, and give birth to live young, so you can’t simply pick them out or scrape off egg clutches. The good news: a combination of reducing their food supply, trapping, and introducing natural predators can bring a population under control, and a full eradication is possible if you’re willing to go further.
Why They’re So Hard to Remove
Malaysian trumpet snails (MTS) belong to the family Thiaridae and reproduce both sexually and through parthenogenesis, meaning a single snail can start a colony on its own. They don’t lay eggs like most aquarium snails. Instead, they give birth to as many as 70 live young at a time, and they can start reproducing at a shell size of just 10 millimeters. Each newborn already has its first two shell whorls and immediately begins feeding.
Their shells are also significantly harder than those of pond snails or bladder snails, which makes them tougher for predators to crack. And because they spend daylight hours buried in sand or gravel, you’ll rarely see the full extent of an infestation until you disturb the substrate or watch the tank after lights-out.
Cut the Food Supply First
Every population explosion traces back to one thing: excess food. MTS eat algae, detritus, and uneaten fish food. If you’re overfeeding your fish, the snails convert that surplus directly into more snails. Reducing how much food enters the tank is the single most important long-term step.
Feed your fish only what they consume within two to three minutes, and remove any visible leftovers. Vacuum the substrate regularly to pull out decomposing organic matter the snails would otherwise eat. Within a few weeks of consistent reduced feeding, you should notice the population plateauing and then slowly declining. This won’t eliminate them entirely, but it stops the exponential growth that makes MTS feel unmanageable.
Manual Removal and Trapping
Because MTS are nocturnal, the most effective manual removal happens after dark. Turn off the tank lights for a few hours, then shine a flashlight on the glass and substrate. You’ll find dozens crawling in the open that were invisible during the day. Pick them out by hand or use a turkey baster to suck up smaller ones.
Vegetable traps work well as a passive method. Place a blanched piece of zucchini, cucumber, or lettuce on the substrate before lights-out. By morning, it will be covered in snails. Lift the whole piece out and dispose of it. Repeat nightly for a week or two and you can remove a significant portion of the population, especially when combined with reduced feeding.
Assassin Snails as Biological Control
Assassin snails (Clea helena) are the most popular biological control for MTS. They’re carnivorous snails that actively hunt other snails by scent, and they share a key behavior with trumpet snails: they bury themselves in substrate, extending a siphon to breathe and smell. When they detect prey nearby, they surface and hunt.
Each assassin snail needs roughly 2 gallons of water and prefers temperatures between 70 and 80°F. For a moderate MTS infestation in a 20-gallon tank, starting with five or six assassin snails is reasonable. They won’t eliminate the population overnight. Expect weeks to months of gradual decline, since assassin snails eat one snail at a time and reproduce slowly themselves. They will also eat deceased animals, fish eggs, and newborn fry that aren’t yet free-swimming, so keep that in mind if you’re breeding fish.
The advantage of assassin snails is that they’re low-maintenance and won’t harm plants. The limitation is that they’ll never fully eradicate every last MTS, especially in a large tank. They’re best used as ongoing population control alongside reduced feeding.
Loaches and Other Fish Predators
Several loach species eat MTS, though results vary because of the snails’ hard shells and burrowing habits. The most effective species based on fishkeeper experience include clown loaches, yoyo loaches, queen botia, kubotai loaches, and orange-fin loaches. Yoyo loaches in particular seem to eat more snails than closely related species like zebra loaches.
There are practical constraints to consider. Clown loaches grow over a foot long and need very large tanks. They can also damage broad-leafed plants. Loaches generally prefer moderate to strong water flow, which doesn’t suit every community tank. In a large tank (100 gallons or more), a small group of loaches may not be able to search out every snail effectively. And some loach species don’t coexist well with bottom-dwelling fish like corydoras. Hillstream loaches and schistura species don’t seem to target MTS at all.
Dwarf pufferfish are another option. They’re aggressive snail eaters, but they’re also aggressive toward tankmates, so they work best in species-only setups or very carefully planned communities.
Chemical Treatment With Copper
Copper sulfate kills snails effectively, but it comes with serious risks. The safe concentration range for a typical freshwater aquarium is 0.15 to 0.2 parts per million. The lethal dose for pond snails is around 0.39 ppm, which is also the upper threshold for fish safety. Go above that and fish can develop red sores on their sides.
The biggest concern: copper is extremely toxic to all invertebrates. If your tank has shrimp, crabs, or any other invertebrates, copper will kill them. It also kills some of the beneficial bacteria in your filter, which can crash your nitrogen cycle. If you do use copper, remove your filter and let it run in a separate bucket of water to keep the bacteria alive during treatment.
Copper also lingers. It absorbs into silicone sealant and porous decorations, slowly leaching back into the water for weeks or months. This makes the tank permanently unsuitable for shrimp unless you do extensive water changes and run chemical filtration media designed to remove heavy metals. For most hobbyists, the collateral damage makes copper a last resort.
Full Tank Reset
If you want every last MTS gone and you’re willing to start your tank over, a full reset is the only guaranteed method. Remove all fish and invertebrates to a temporary holding tank. Drain the main tank completely. Boil gravel or sand for 10 to 15 minutes, or replace the substrate entirely. Scrub hardscape (rocks, driftwood) and soak them in a dilute bleach solution, then rinse thoroughly and dechlorinate before reuse.
The challenge is live plants. Snails and their young hide in root systems and leaf folds, and a simple rinse won’t get them all. The most reliable plant treatment is an alum soak: one tablespoon of potassium alum per gallon of water for two full days. This kills both snails and their eggs without harming the plants. Carbonated water also works. Soak plants in fresh carbonated water (or any carbonated drink) for 12 hours, then repeat the soak with fresh carbonated water two more times. Three total 12-hour soaks will kill snails, planaria, and other hitchhikers.
Hydrogen peroxide is another option but riskier for plants. A strong solution (25% dilution of standard 3% hydrogen peroxide) soaked for a day kills snails and eggs but can also damage delicate plant tissue.
Preventing Reintroduction
MTS almost always enter aquariums as hitchhikers on new plants. A single tiny snail, invisible among the roots, is enough to start the cycle over. Quarantining and treating every new plant before it goes into your display tank is the only reliable prevention.
The alum soak (one tablespoon per gallon for two days) is the gold standard for plant quarantine. It’s plant-safe and kills both snails and eggs. If you’re in a hurry, the carbonated water method works in 36 hours total across three soaks. At minimum, inspect every plant carefully under bright light, checking the undersides of leaves, between root clusters, and inside any curled or folded foliage. Even with inspection, soaking is strongly recommended, since juvenile MTS are translucent and only a few millimeters long.
Tissue-cultured plants sold in sealed gel cups are the only truly snail-free option, since they’re grown in sterile lab conditions. They cost more, but if you’ve already gone through the effort of a full tank reset, the peace of mind is worth it.