is one piece episode 597 filler?

Brook recognizes Slime, saying he read about it in a book once. They attack women and use their bodies to melt the woman's clothes.

Sanji and Kin'emon are intrigued and ask to borrow the book later. Zoro directs their attention to the lake, saying that the slime from the creature is probably dangerous to touch, as the slime that fell into the lake has killed all the fish.

Brook asks Sanji if he is really going to look for Kin'emon's torso. Sanji says he is, and it is something only he can do.