Neritina pulligera, also known as dusky nerite, black racer, black helmet snail, or steel helmet snail, is a species of freshwater snail of the family Neritidae. The snail was first described in 1767 by Carl Linnaeus and is the type species (reference species) of the genus Neritina.

N. pulligera has a thick, olive-green to black shell typically 20 – 26 mm long. The shell covers almost the entire body and only the tentacles stick out. This species has an operculum, a "trapdoor" used by the snail to close its shell. Females have a specialised organ called the crystal or reinforcement sac, which stores solid material used to produce a hardened egg capsule.

N. pulligera is native across the Indo-west Pacific and lives in fast-flowing streams and rivers. It is sold worldwide as part of the aquarium trade, raising concerns about potential biological invasions, but has not been recorded outside of its native range as of 2023.

Females attach their eggs on the shells of other living snails, a unique behaviour shared by neritids. Together with the reinforced egg capsules, this helps protect the eggs from predation by other snails. Like other neritids, the larvae drift downstream to the sea and juveniles migrate back upstream to reproduce. Juveniles of Neritina asperulata often save energy in this migration by "hitchhiking" on the bigger N. pulligera.

The snail is a popular ornamental species in aquariums and often introduced to combat algae growth. However, N. pulligera feeds exclusively on algae and biofilm and individuals may starve if algae don't regrow fast enough or if their diet is not complemented e.g. with algae stones. Because juveniles do not develop in fresh water, all traded individuals are wild caught, which raises concerns about impacts on local N. pulligera populations.

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