Faunus ater (Devil's Thorn Snail)

05 April 2026

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Meet the Devil's Thorn Snail (Faunus ater), a striking and peaceful addition to your freshwater or brackish aquarium. Known for its sleek, elongated shell and deep, mysterious coloration, this active scavenger works tirelessly to consume detritus and algae while remaining completely safe for your live aquatic plants.

Overview

The Devil's Thorn Snail, scientifically known as Faunus ater, is a fascinating and highly sought-after invertebrate in the aquarium hobby. Often referred to as the Black Devil Snail, it is prized for its unique, elongated appearance and its peaceful, industrious nature. Despite its somewhat intimidating common name, this snail is entirely harmless to tank mates and live plants, making it a premier choice for community and planted aquariums alike.

Image of devil s thorn snail faunus ater

Distribution and Habitat

Native to the Indo-Pacific region, Faunus ater is widely distributed across Southeast Asia, including countries like Thailand, Indonesia, Malaysia, and the Philippines. In the wild, they are typically found in the lower reaches of rivers, estuaries, and coastal lagoons. Because their natural habitat spans areas where rivers meet the sea, they are highly adaptable and can thrive in both pure freshwater and brackish water environments.

Description of Devil's Thorn Snail

The Devil's Thorn Snail boasts a distinctive, sharply conical shell that can grow up to 3 to 3.5 inches in length. The shell is generally smooth and lacks the pronounced ridges seen in some Tylomelania (Rabbit Snail) species. Coloration ranges from a deep, glossy black to a rich, dark brown. As seen in many specimens, the shell may feature a stunning gradient, transitioning from a dark anterior to a reddish-mahogany or burnt orange hue near the tip. Their soft bodies are equally dark, often black or deep grey, speckled with subtle lighter spots.

Keeping and Caring for Devil's Thorn Snail

Caring for the Devil's Thorn Snail is relatively straightforward, provided their basic water chemistry needs are met. They are hardy, active, and peaceful, making them excellent tank mates for small fish, dwarf shrimp, and other non-aggressive snails. Because they naturally inhabit areas with harder water, maintaining proper mineral levels is the most critical aspect of their care.

Tank size:

A minimum tank size of 10 gallons is recommended for a small group of Devil's Thorn Snails. Due to their elongated shells, they need adequate substrate space to roam and forage comfortably without getting wedged into overly tight crevices.

Water Parameters:

Temperature

They thrive in warm tropical waters. Keep the aquarium temperature consistently between 72°F and 82°F (22°C - 28°C) for optimal health and activity.

pH

A slightly alkaline environment is crucial to prevent shell erosion. Maintain a pH between 7.0 and 8.0. Acidic water will slowly dissolve their beautiful shells over time.

Hardness

Hard water is a must. Aim for a General Hardness (GH) of 8-15+ dGH and a Carbonate Hardness (KH) of 5-15 dKH. Adding crushed coral or cuttlebone to the filter or substrate can help maintain these essential mineral levels.

Ammonia, Nitrite, Nitrate

Like all aquatic invertebrates, they are highly sensitive to poor water quality. Ammonia and Nitrite must always be at 0 ppm. Nitrates should be kept as low as possible, ideally below 20 ppm, through regular water changes and aquarium maintenance.

Feeding the Devil's Thorn Snail

The Devil's Thorn Snail is an omnivorous scavenger and an excellent cleanup crew member. In the aquarium, they will naturally graze on soft algae, biofilm, and decaying plant matter. However, their diet should be supplemented to ensure they receive adequate nutrition. Feed them sinking algae wafers, bottom-feeder pellets, and blanched vegetables such as zucchini, spinach, or cucumber. They are completely plant-safe and will ignore healthy, living aquatic plants.

Breeding Devil's Thorn Snail

If you are hoping to breed the Devil's Thorn Snail in a standard freshwater aquarium, you will be out of luck. While they may occasionally lay eggs, Faunus ater requires brackish water for their larvae to successfully hatch and develop. Because of this complex reproductive cycle, they will not overrun your freshwater tank with unwanted offspring, which is a major benefit for many aquarists.

Conclusion

The Devil's Thorn Snail is a visually striking, incredibly useful, and low-maintenance invertebrate. Their sleek, dark shells provide a beautiful contrast against green aquarium foliage and light-colored substrates. With their peaceful demeanor, plant-safe grazing habits, and inability to overpopulate a freshwater tank, Faunus ater makes an exceptional addition to almost any tropical aquarium setup.

Snail info

Temperature : 72°F - 82°F (22°C - 28°C)
pH: 7.0 - 8.0
Color Form: Black

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