is one piece episode 256 filler?

Rocketman is seen going through an underground canal much to the surprise of the Straw Hats. Luffy ends up getting water in his nose much to the annoyance of Nami.

Luffy feels as he is falling and Kokoro says they are almost at the exit. Suddenly, Rocketman comes charging out of Water 7 and into the sea.

Zambai and the rest of the Franky Family follow behind with their King Bulls, Sodom and Gomorrah. Zambai thanks Luffy for allowing them to come and fires the connection cannons that link their ship with Rocketman.

Zoro yells at them for almost hitting him.