沼 is built from the 氵 (water (left)) and 召 components.
It reads ショウ like 召, as do 昭, 招, 紹, and 照 — learn 召 once and the family's reading comes with it.
A common word using 沼 is 沼 (ぬま), meaning “swamp, bog, pond”.
Don't confuse it with 招, 紹, 昭, and 照.
