Black Military Helmet Snails

Quick facts

Identity

Also known as

Dusky Nerite; Black Racer Nerite; Black-Capped Nerite; Baseball Cap Nerite; Steel Helmet Snail; Red-Lipped Nerite

Synonyms

Nerita pulligera

Environment

Freshwater

Native to

East Africa, Madagascar, India, Southeast Asia, Japan, New Guinea, Australia, Polynesia

Habitat

Fast-flowing coastal streams and lower river reaches with rocky substrate, clamped to boulders in strong current; larvae develop in brackish estuarine water

Sourcing

Wild-caught

Conservation

Least Concern

Care

Care level

Easy

Temperament

Peaceful

Adult size

1 – 1.6 in (2.5 – 4.1 cm)

Lifespan

3 – 5 yrs

Min tank

10 gal (38 L)

Growth rate

Slow

Placement

Rock & glass

Water

Temperature

72 – 82 °F (22 – 28 °C)

pH

7.0 – 8.2

GH

8 – 14 dGH

dKH

4 – 12 dKH

Flow

Moderate

Behavior & compatibility

Social

Solitary

Aggression to own kind

Low

Active

Night

Invert safe

Yes

Plant safe

Yes

Shrimp safe

Yes

Clean-up role

Algae, Biofilm, Leftover food

Population boom risk

Low

Feeding & breeding

Diet

Herbivore

Foods

Algae, Biofilm, Vegetables

Breeding type

Broadcast spawner

Breeding difficulty

Not bred in captivity

Sexing

Sexually dimorphic; males are smaller and generally show more vivid shell coloration than the larger, duller females

Target feeding

Beneficial

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Care guide

Overview

Wild-collected from coastal streams and river mouths across the Indo-Pacific, this nerite carries a glossy dark brown to black dome shell shaped like a soldier's helmet. It clings to rockwork grazing algae and biofilm around the clock, needs hard, calcium-rich water to keep its shell intact, and cannot reproduce in freshwater aquariums.

Care

This nerite is a heavy-duty algae grazer that does best in a mature, fully cycled tank with some water movement, since it evolved clinging to rocks in fast-flowing streams. Its thick, dome-shaped shell needs plenty of dissolved calcium, so keep GH on the higher side and avoid soft, acidic water that can etch or thin the shell over time. Provide rockwork or hardscape for grazing surfaces, and be aware that a single adult can strip algae from a small tank faster than it regrows, so supplemental feeding may be needed in low-algae setups.

Feeding

In the aquarium it grazes continuously on algae films and biofilm coating glass, rocks, and plant leaves, and it will also pick at leftover fish food. If algae growth cannot keep pace with its appetite, offer blanched vegetables like zucchini or algae wafers to prevent starvation. Slow-growing, broad-leaved plants such as Anubias and Cryptocoryne provide good biofilm-grazing surfaces alongside hardscape.

Tank mates

Its peaceful, slow-moving nature makes it compatible with shrimp, small community fish, and other snails, and it poses no threat to plants beyond incidental grazing. Avoid pairing it with aggressive or large predatory fish that may harass or eat it, and keep copper-based medications and fertilizers out of the tank since snails are sensitive to copper. Because it needs calcium-rich water, tankmates should share similar hard-water, neutral-to-alkaline preferences.

Breeding

Females lay hardened, calcareous egg capsules, often attaching them to the shells of other snails to reduce predation risk, but the larvae require a brackish or marine environment to develop and cannot mature in freshwater. As a result, eggs deposited in a home aquarium never hatch, so populations cannot become established in captivity. Every specimen in the trade is wild-caught since no commercial operation replicates the amphidromous larval stage.

Health

The main captive health issue is shell erosion or pitting caused by soft, acidic, or calcium-poor water, which can progress if not corrected with harder water or calcium supplementation. Sudden exposure to ammonia, nitrite, or copper-based treatments is quickly fatal, so the tank must be fully cycled before introduction. Watch for a snail remaining closed or unresponsive for extended periods, which can indicate poor water quality or a failing individual.

Sources

1. Neritina pulligera - Wikipedia
2. Black Racer Nerite Snail Care | A Different Kind Of Nerite - The Shrimp Farm
3. Black Military Helmet Nerite Snail: Neritina pulligera Care Guide | Studio Scaped
4. Neritina Pulligera – Detailed Guide: Care, Diet, and Breeding - Shrimp and Snail Breeder

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