Black Devil Snail – Detailed Guide: Care, Diet and Breeding

Black Devil Snail (Faunus ater)

Black Devil Snail (Faunus ater) is not very common in the aquarium trade yet. However, in my opinion, they are some of the most underrated snails in the aquarium hobby.  Do you know why?

Because Black Devil Snails are easy to care for. They are pretty hardy snails and can withstand varied ranges of salinity, from freshwater to saltwater. In addition, these snails will only breed in brackish water that is why it is more usual to see them in freshwater tanks.

Nonetheless, there are also other ways Black Devil Snail can benefit your aquarium. Although the ecology of this species is poorly researched, in this article, I will tell you everything I know about this species.

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Quick Notes about Black Devil Snails

Name Black Devil Snail
Common names Black Devil Spike Snail, Black Spike Snail, Black Devil Snail, Lava Snail,  Spike Live Snail
Scientific name Faunus Ater
Tank size (minimal) 10-gallons (~40 liters)
Keeping Easy
Breeding Difficult
Size 5 – 9 cm (2 – 3.5 inches)
Temperature 71° – 82° F (22° – 28° C)
Optimal PH 7.0 – 8.5 
Optimal GH 3 – 18 
Optimal KH 3 – 12 
TDS (optimal) 100 – 300 
Nitrate Less than 20 ppm
Diet Omnivore / Algae eater
Temperament Peaceful 
Life span up to 6 years
Color Form Black to brown

Why are these snails called Black Devil Snails?

Do you know that Black Devil Snail is considered as a native delicacy in the Philippines and some other countries? Well, according to some reviews, dead (and half-cooked) Black Devil snails release a truly diabolical aroma. So, local people started calling it that way.

Interesting facts: Faunus ater is from the Greek word “Faunus” [ˈfau̯nʊs] – Roman horned God of forests, fields, farming, and livestock. Ater is also a Latin word meaning “black, dark and malicious”. 

Rabbit Snails and Black Devil Snails

Black Devil Snails are a lot like Rabbit snails (read the guide for more info) in terms of their shell design. Both species look very similar. However, it should not confuse you. These species are not closely related and cannot interbreed.

In all other articles, you can also read that Black Devil Snails are relatives to the popular Malaysian Trumpet Snails (read my article pros and cons about them). Well, they are all wrong.

According to the study, the genus Faunus is monotypic, comprising of a single species, Faunus ater.

Its higher classification is confusing, and Faunus ater has been placed in the families Cerithiidae, Thiaridae, Melanopsidae, Potamididae, Melaniidae, and Pachychilidae.

Very recent studies using expanded morphological data as well as molecular data sets provide strong evidence that Faunus belongs in the family Pachychilidae. 

Natural Habitat of Black Devil Snails

The distribution of Black Devil Snails is limited to the tropical Indo-west Pacific region. In Asia, they have been reported from countries like Sri Lanka, India, Myanmar, Thailand, Malaysia, Singapore, Philippines, Indonesia, New Guinea, northern Australia, and China.

Natively Black Devil Snails prefer tropical brackish or freshwater water habitats like mangroves, intertidal areas, lagoons, ditches, streams, river mouths and estuaries with a brackish influence where the depth ranges from 0.3 to 1.5 m.

Black Devil Snails Description

Black Devil Snail (Faunus ater)Black Devil Snails have a relatively large, shell, reaching to 9 cm (~3.5 inches) in length but usually averaging about 5 – 6 cm (~2 – 2.5 inches). The average shell width ranges from 0.5 – 2 cm. Shell color is black in juveniles, turning to mahogany (black and brown in color) as the shell grows.

The shell is elongate, smooth-surfaced and comprises of around 6 to 20 straight-sided to slightly inflated whorls inflated towards the aperture side. The adult shells often have eroded apical whorls. The aperture is white and ovate.

Black Devil Snail has an operculum (the plate that they use to close the opening of the shell). The operculum is corneous, ovoid, thick and black.

Tip: The operculum is a good way to find out if your snail is alive or dead. It will simply fall off when the snail dies.

The shells are unique on account of its large size, narrow conical profile. The periostracum (special layer) protects the shell from the acidic environment of its habitat.

The broad, muscular snout, large buccal mass, and robust radula indicate that this species can graze on coarse substrata. The foot has a gray-black color with a light dotted pattern and lighter than the body. 

Black Devil Snails and Color Morphs

Faunus ater - CappuccinoSometimes in pet stores, we can see different color morphs of this species (Bicolor Snail). For example, Faunus ater “Cappuccino” has a gradient shell from dark-brown to orange or white.

Actually, it is not clear and some aquarists have some serious doubts about it. The point is that the genus Faunus is monotypic, comprising of a single species – Faunus ater. According to all scientific studies and researches, Faunus ater does not have color morphs. They are all dark. Therefore, those snails are something else but Faunus ater.

However, there is always a chance that scientists are wrong and later this color morph will be included in this genus.

The Behavior of Black Devil Snails   

Faunus ater snail on glass

Black Devil Snails are diggers and nocturnal. They usually spend most of the time buried in the substrate crawling through it. By doing so they prevent the risk of a gas pocket being built up which can be very dangerous to your fish or shrimp.

From time to time you might see them go the top of the tank only to slid down the glass or free fall to the bottom. They are active everywhere on or under the ground.

Note: Black Devil Snails can potentially uproot plants with a weak root system.

Black Devil Snails Diet 

Black Devil Snails are omnivorous and great scavengers. According to some observations in the wild, these snails are attracted towards mud, garbage disposal and known to be present in areas with anthropogenic impacts.

These snails are also good as algae-eaters. However, do not expect them to clean your glass, they are simply too heavy for that. In the aquarium, Black Devil Snails feed mostly on the substrate. They will feed on leftover shrimp or fish food, such as pills, flakes, pellets, algae/Spirulina wafers, frozen foods, etc.

The shells deterioration on the Black Devil Snails is pretty common Adding calcium supplements can help ensure their shells are strong and healthy.

I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.

Black Devil Snails and Live Plants

Faunus ater lava snail manyDo Black Devil Snails eat live plants? Are they safe to keep in planted tanks?

It depends on how hungry they are. Black Devil Snails usually do not feed on live plants if there are other available sources. So, keep them well-fed, especially in a tank with expensive and rare plants.

Tip: Provide a variety of leaf litter for the snail to graze on. Get them some blanched vegetables systematically and they most likely will not bother your plants.

In addition, I would also like to mention how Black Devil Snails can benefit your plants. Their poop is a good fertilizer for plants. I have already said that these snails like to burrow. By pooping in the substrate, snails introduce some fertilization, which helps your plants.

You can read some of my related articles (the principle is the same with snails):

Indian almond leaves and Alder Cones.
How to Blanch Сucumbers and Zucchini for Shrimp.

Keeping and Housing Black Devil Snails 

Although these snails are hardy by nature, it would be better to avoid rapid changes in water parameters. Sometimes aquarists say that Black Devil Snails are very tolerant against salt. Well, it is not correct. In the wild, they prefer to live in brackish water but it is also possible to keep it in freshwater tanks.

Substrate

The substratum is sandy (coarse and fine sand) or soil with a little gravel, silt clay. Keep in mind that, having hard substrates like pebbles, gravel will make it hard for them to bury.

Tank Size

Black Devil Snails will do well in larger tanks. Keep in mind that they can grow up to 9 cm! Therefore, it is best to keep them in an established 10-gallon (~40 liters) tank. This gives them enough space to move and eat as they please.

Water Parameters

In the wild, the salinity of water, where Black Devil Snails live, ranges from slightly brackish water to full-strength seawater (specific gravity: 1.002–1.025). They are well-adapted snails.

Keep your water hard and pH more than 7.0. Ideally, Black Devil Snails do best in pH 7.0 – 8.0. PH. The problem is that their shells dissolve in the water that is not hard enough. PH level will effects shell deterioration.

Note: Cracked, eroded, thin, or pitted shells is a sign of low pH as well as low levels of calcium.

These snails prefer warm water, so you might need an aquarium heater. If your room temperature is about 21 – 22C (70 – 72F) they will still be OK. However, their metabolism will slow down, which leads to your snail becoming a bit sluggish and lethargic.

Do not forget that they need careful acclimation (read more about it here) as all invertebrates. 

Basic Tank Equipment (links to check the price on Amazon)

Black Devil Snails Breeding

Surprisingly, the reproductive biology of Black Devil Snails is largely unknown. In addition, males and females cannot be distinguished by external features as well.

The scarce information tells us that Black Devil Snails are oviparous and their large geographical distribution suggests an extended free-swimming larval stage. Black Devil Snails do not breed in freshwater. The larvae can develop in a marine environment only.

Black Devil Snails and Suitable Tank Mates

Faunus ater lava snailThese are peaceful aquarium snails and completely safe to keep with non-aggressive freshwater fish and dwarf shrimp (for example, Cherry shrimpSnowball shrimpCaridina cf. BabaultiGhost shrimpAmano shrimp, Bamboo shrimpBlue tiger shrimpBlue Velvet Shrimp etc).

Tip: Black Devil Snail has a small and thin antennae. So, try to avoid any fish that can nip at them.

You can combine Black Devil Snails with any type of snails as well (Ramshorn snailsNerite snailsJapanese trapdoor snailsMystery snailsMalaysian Trumpet snails, and etc.).

Do not keep them with crayfish and crabs that can break their thick shells. If a predator is around, these snails will usually hide into the shell and close the operculum until they are safe. Structure analyses of the shell scars show that it is usually a result of attacks by crabs. 

Conclusion

Faunus ater (Black Devil Snail) is a hardy, active and large freshwater snail species. The snail can live in both fresh and brackish water. They are excellent scavengers and will be your clean up crew. They will not overpopulate your tank. In addition, they will aerate your substrate and fertilize your plants. What else can you expect from the snail? Black Devil Snail is almost an ideal addition to any freshwater aquarium! 

Related articles:

References:

  1. Survey of brackish-water snails in Eastern Thailand. Article in The Southeast Asian journal of tropical medicine and public health. January 2004
  2. Status and Distribution of Faunus ater in Singapore, Alvin Francis S. L. Lok, W. F. Ang, P. X. Ng, Beatrice Y. Q. Ng, S. K. Tan. Limited distribution of Devil snail Faunus ater (Linnaeus, 1758) in tropical mangrove habitats of India. Article in Indian Journal of Geo-Marine Sciences. October 2018.
  3. First report of Faunus ater (Pachychilidae: Gastropod) on the American Continent: A mature empty specimen from Masachapa, Nicaragua, Central America Article. December 2012. DOI: 10.22458/urj.v4i2.7.
  4. Relative warp analysis on shell shapes of Faunus ater in Guihing River Hagonoy, Davao del Sur. Article. January 2016.
  5. Hand book freshwater molluscs of India. By N. V. SUBBA RAO Zoological Survey of India, Calcutta. ZOOLOGICAL SLFRVEY OF INDIA, C Government of India, 1989.
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