A species of rare freshwater snail has been granted legal protection by the Minister for Wildlife Joan Ruddock.
The lesser whirlpool ram's-horn snail has a flattened spiral shell rarely more than 5mm in diameter.
It is found in calcareous waters in marsh drains with dense aquatic foliage in Norfolk, Suffolk and Sussex.
From 1 October, the snail will be protected from being killed, taken, disturbed, owned or sold, or having resting or breeding places destroyed.
The nature reserve managed by Suffolk Wildlife Trust at Carlton Marshes near Lowestoft is the UK stronghold for the species.
The marshes is also important for other rare freshwater snails such as Segmentina nitida and Pisidium pseudosphaerium.
Minister for Wildlife Joan Ruddock said: "Working in harmony with nature is becoming more and more important as increasing demands are made on our environment.
"The UK's native species need our support and I hope this announcement will help give them a secure future."
The Fisher's estuarine moth and the pool frog will also be legally protected from 1 October.