Pokemon XY - episode 50 - 19 Nov, 2014

After encountering the Mock Kelp Pokémon Skrelp on the Muraille coastline, Ash and his friends join two marine archaeologists on an expedition to the sunken luxury liner known as the Cussler where Skrelp, Dragalge, and several marine Pokémon live. However, Team Rocket has their sights set on capturing all of the Pokémon that call the Cussler home. (Source: Wikipedia)