Care guide · Freshwater snails

Dusky nerite snail

Neritina pulligera

Photo: Jan Delsing / BioLib via Wikimedia Commons; released into the public domain. Photo: Jan Delsing · Source · Public domain (author release)None; original 912 × 532 pixels.

The dusky nerite snail (Neritina pulligera) is a larger nerite from tropical rivers and river mouths in the Indo-Pacific. It grazes on hard surfaces and therefore needs a mature aquarium with enough biofilm. Adults may reach about 3–4 cm. Published aquarium advice differs on temperature, pH and minimum tank volume; the figures here are a cautious shared husbandry range, not experimentally established physiological limits. The snail is peaceful, but a clean aquarium with little natural growth may not provide enough food. Eggs may be laid in freshwater, yet the life cycle is not completed there. The trade name is sometimes applied broadly, so confirm species identity when buying.

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At a glance

Temperature: 22–26 °C
pH: 7.0–8.0
Diet: Herbivore
Adult size: Up to 4 cm
Temperament: Peaceful

About this species

Neritina pulligera (Linnaeus, 1767) belongs to the family Neritidae. Its dark, domed shell explains trade names such as dusky nerite and military helmet snail. A revision using morphology and DNA showed that several species were formerly combined under the name N. pulligera incorrectly. The name on a shop label therefore does not guarantee that every dark nerite is this species. This guide applies to correctly identified N. pulligera; colour alone is not a reliable identification.

Natural habitat

The species is recorded from tropical freshwater streams and river mouths in the Indo-Pacific and can occur in estuarine areas influenced by brackish water. An Australian mollusc key describes animals under rocks, among leaf litter, and in fresh to brackish water. This points to sheltered hard surfaces, not one exact aquarium biotope. The snail grazes on rock, wood and other surfaces where growth develops. It has an amphidromous life cycle: adults live in rivers while larvae move downstream toward saltier water. A home aquarium therefore cannot reproduce its full life cycle.

Aquarium and layout

Use a mature, biologically established aquarium with plenty of rock, wood and other stable grazing surfaces. The snail may reach about 3–4 cm; a larger nerite needs more food-bearing surface than a small specimen. There is not enough agreement to state one exact minimum volume: aquarium sources give different limits and biofilm availability varies greatly between tanks. We therefore avoid a falsely precise litre figure. Do not place it in a sterile, newly started aquarium. Protect filter intakes and avoid shifting heavy rocks carelessly. Acclimate it gradually to the aquarium water.

Water conditions

A cautious overlap of published care advice is about 22–26°C and pH 7–8. These are practical aquarium targets, not experimentally established species limits. Sources also publish wider values but disagree at the extremes. Keep temperature and pH stable and avoid persistently very soft or acidic water because nerites build a calcareous shell. The reviewed sources do not provide a robust species-specific GH or KH target that can be stated as a firm requirement. Monitor the shell and water quality; do not add minerals or buffers without a measured reason.

Behaviour and group size

The dusky nerite moves slowly over glass, stone, wood and decor, grazing on growth. Aquarium profiles describe it as peaceful, not an active predator. It does not need a school or a conspecific to function. A larger animal may need more grazing area than a small nerite. Watch whether it attaches and moves over surfaces; persistent falling or inactivity warrants a check of water, temperature and food. Other bottom-dwelling animals may use the same biofilm and algae supply.

Feeding

Natural and usual aquarium food consists mainly of algae film, diatoms and biofilm growing on surfaces. A mature tank with enough natural growth is therefore more important than a fixed daily portion. In a food-poor tank, suitable snail or algae food may be needed as a supplement; feed sparingly and remove leftovers before they degrade water quality. A snail placed only on clean glass may not get enough to eat, even if the aquarium looks tidy. Check activity and condition, and avoid cleaning every grazing surface at once.

Breeding

Adult nerites may leave small, hard, pale egg capsules on stone, glass or decor. Their presence alone does not indicate a pest outbreak. This species has an amphidromous life cycle: larval development is not completed in ordinary freshwater aquarium conditions and is associated with saltier water. A standard freshwater tank therefore usually does not produce successful captive young. Remove capsules only if they are unwanted; they can be firmly attached. There is no simple, well-supported hobby protocol that guarantees breeding, so do not describe the species as easy to breed.

Keeping with fish

The snail is peaceful, but that does not make every fish a suitable tankmate. Avoid fish and other animals that actively eat snails, pull at the foot or repeatedly knock the snail over. Small peaceful fish may be considered only when temperature and water chemistry fit and there is no clear risk of attack. No controlled trial covers every species pairing; also assess adult size, behaviour, bottom use and food competition. Ensure the snail can reach several grazing areas undisturbed and remove it if a tankmate keeps harassing it.

Keeping with other invertebrates

A conditional pairing with the red cherry shrimp (Neocaridina davidi) may work when water values fit: the stored temperature ranges overlap at 22–24°C and pH ranges at 6.5–7.5. An aquarium retailer says nerites are compatible with dwarf shrimp, but this is not a controlled trial of these exact species. Both may use biofilm, so food competition matters in a clean tank. Provide ample grazing surfaces and supplement only when needed. Check that shrimp can reach food and the snail remains active; separate them if either declines.

Exoskeleton, shell and minerals

The snail does not moult like a shrimp, but its shell grows and remains vulnerable to persistently unsuitable water chemistry. Very soft, acidic water can erode calcareous shell material. A crumbling edge, pits or visible wear is a reason to measure pH, hardness and minerals; appearance alone is not a diagnosis. Change water conditions gradually and avoid uncontrolled calcium dosing. A healthy shell protects the animal, but a sudden addition of lime will not immediately repair damage.

Possible problems

The main practical risk is starvation in a new or overly clean aquarium. Unsuitable water chemistry, large fluctuations, metals harmful to invertebrates and attacks by snail-eating tankmates can also cause problems. First check temperature, pH, ammonia/ammonium and nitrite, and confirm that grazing growth is actually available. Avoid repeatedly moving the snail between tanks with different conditions. An inactive animal is not automatically dead; gently check whether it attaches. For persistent shell damage or repeated losses, seek specialist advice rather than trying random treatments.

Sources & review

This care guide draws on several specialist sources and was last checked on 17 October 2026.

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