Episode 32

"The Witch of Cocoyasi Village, Arlong's Female Officer" is the 32nd episode of the One Piece anime.

Short Summary
Zoro is captured by the Fishmen after Usopp and Johnny ditch him, and it's revealed that Nami was part of Arlong's crew the entire time. When a group of Fishmen attack Cocoyasi Village, Usopp comes to the rescue.