Isla de Yoshi

Yoshi's Tropical Paradise (Isla de Yoshi is its real name) is a water-themed region of the Eleanor Kingdom in Super Mario Bros. X: Alternate Kingdom. It is inhabited by Yoshis and it is also the home of the aquatic species of fishes, the Cheep-Cheeps. It is the third world Mario and friends goes to.

It is confirmed that Doshi went through that way.

Curse
By the time Blaize invaded the kingdom, the aquatic land of the Yoshis got cursed; the weather is hotter, the waters got darker and murky, now undead fishes, the Fishbones, are appearing everywhere, haunting many residants of Isla de Yoshi. The curse prevents anyone to go to having fun at the beaches, go bathing, go fishing or swimming since many members of the Blaize Army are there as well.

Trivia

 * Isla de Yoshi is similar to that of the Great Bay from Majora's Mask.
 * That world will also be like the last world of The Invasion.