is one piece episode 528 filler?

The episode begins with an infatuated Sanji playing in a pool with the mermaids in Mermaid Cove. The chef states his wish to live there, with a mermaid remarking how much fun he is.

Luffy, soaking his feet on the side of the pool, comments on how nice it must be to swim. Camie suggests that Luffy could wear a bubble in order to do so, much to his surprise.

Usopp asks if Sanji is just acting the way he is out of nature. Chopper states that he is glad Sanji is back to normal, going on to say that his blood stock is out of Sanji's blood type, S RH-, an exceedingly rare blood type.