is one piece episode 341 filler?

After the dinner with Dr. Hogback, Nami decides to take a bath with Usopp and Chopper guarding the bathroom door.

Chopper states that he wants to take a peek in Hogback's lab while Usopp complains to Nami that if she is scared, she should not take a bath, which she replies that when night falls, they will leave the mansion. The two boys complain saying that they won't make a move for now and that they will wait for Luffy and the others.

Nami then says that there are abnormal presences in the mansion as well, scaring the two. She states that she also suspects that Dr.