Black Devil Snail Care Guide: Faunus ater in Planted Tanks
The black devil snail is one of the most visually striking invertebrates in the freshwater hobby — a jet-black, elongated shell up to 8 cm long that glides across substrate with an unhurried, sculptural quality. A reliable black devil snail care guide needs to address what sets Faunus ater apart from the typical pond and nerite snails most hobbyists know: different water needs, different feeding behaviour, and genuinely unique reproductive biology. At Gensou Aquascaping at 5 Everton Park, Singapore, we keep these regularly and field questions about them constantly.
Species Background and Natural Habitat
Faunus ater is a freshwater horn snail distributed across Southeast Asia, including Malaysia, Indonesia, and the Philippines. In the wild they inhabit rivers and streams with moderate to strong current, feeding on algae, biofilm, and detritus. The shell is distinctly turreted — spiralling to a sharp point — and glossy black to dark brown. Like nerites, they do not breed in fresh water, making them incapable of becoming a pest species in your tank. This alone makes them appealing for planted setups where snail population explosions are a real concern.
Water Parameters and Singapore Suitability
Black devil snails prefer moderately hard, slightly alkaline water: pH 7.0–8.0, GH 8–15, temperature 24–28°C. This is actually harder than Singapore’s typical tap water (GH 2–4), so some mineral supplementation is beneficial. A small amount of crushed coral in the filter — just 50–100 grams in a media bag — steadily raises GH and KH into a more suitable range. Alternatively, a Wondershell or similar mineral block achieves the same effect passively.
Adequate calcium is essential. Soft, acidic water causes shell erosion — the characteristic pitting and dulling of the shell surface seen on poorly kept specimens. Feed calcium-rich supplementary foods (blanched kale, cuttlebone pieces) as an additional source beyond water hardness.
Feeding and Behaviour
Black devil snails are primarily detritivores and biofilm grazers, spending most time burrowing through substrate with their pointed shell and feeding on decomposing matter and fine algae. Unlike nerites, they do not reliably graze visible algae patches on glass — don’t count on them as algae control specialists. They’re more accurately described as substrate cleaners and enrichment animals.
Supplement their diet with blanched vegetables (spinach, courgette, kale), algae wafers, and sinking pellets. They’re most active at night; during the day they often bury themselves completely in soft substrate. Fine sand 3–4 cm deep accommodates this naturally.
Tank Size and Compatibility
A single black devil snail is comfortable in a 30-litre tank; keep groups of three to five in 60 litres or more. They’re entirely peaceful and compatible with virtually all community fish, shrimp, and other snails. The main compatibility concern runs the other way: some pea puffers, large cichlids, and assassin snails will attack them. Keep them with peaceful nano fish or in snail-only setups. Assassin snails will actively hunt and kill black devil snails despite their thick shells.
Reproduction: Why They Won’t Overpopulate Your Tank
Faunus ater is amphidromous — their larvae require brackish or marine conditions to develop. Adults mate in fresh water and females deposit tiny white egg capsules, but the veliger larvae that hatch cannot survive in fresh water alone. They need to migrate toward estuarine conditions, which is impossible in a closed aquarium. In practical terms: your black devil snail population will never grow beyond the individuals you add. No population explosions, ever.
This reproductive biology makes them quite expensive relative to common snails — typically $3–8 each in Singapore, as every individual must be bred under controlled brackish conditions by specialist producers. The price is a fair reflection of the effort involved.
Common Problems and Health Signs
Shell pitting or cracking indicates inadequate calcium, usually from water that’s too soft. Fix the water hardness before adding more specimens. Snails that stay constantly inactive at the surface may be stressed by ammonia or nitrite — check water quality immediately. Foot retraction and operculum closure are normal stress responses; the snail will usually emerge within 12–24 hours once conditions improve. A snail that smells foul and fails to respond to gentle touch after 48 hours has almost certainly died and should be removed to prevent water quality decline.
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Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
