In the original Japanese version, Nami kicks Usopp into the water after stabbing him; however, in some international versions like the 4Kids dub, the blood was edited or removed.
This episode is highly regarded for its "shock value," setting up the emotional backstory for Nami that is fully revealed in the subsequent episodes. One Piece Episode 33
Johnny, who witnessed Nami's actions from a distance, reports to the rest of the crew that Nami has murdered Usopp. In the original Japanese version, Nami kicks Usopp
Earlier in the episode, Zoro escapes his confinement after Arlong discovers the damage he caused to the base while Nami was secretly assisting him. Watch Guide & Trivia In the original Japanese version