noun
pond snail; river snail
Refers to freshwater snails of the family Viviparidae, commonly found in ponds and rice paddies in Japan.
田んぼでタニシを見つけた。
I found a pond snail in the rice paddy.
タニシは水質をきれいにするのに役立つ。
Pond snails help keep the water clean.
The origin is uncertain. The kanji 田螺 literally means 'rice-field spiral shell', reflecting its habitat.