Well I Found On The NintendoWiki Facts About The Colored Yoshis!! Here's the Facts
Green Yoshi:
The most common color of Yoshi. First appeared in Super Mario World.
Blue Yoshi: Was first introduced in Super Mario World. In that game, when a blue Yoshi obtains a shell, it gains the ability to fly regardless of its color. Blue Yoshis are a common color of Yoshi and appear as alternate as cores for Yoshi in the Super Smash Bros. series (note: there is also a sticker of Blue Yoshi in Super Smash Bros. Brawl), Mario Super Sluggers, Super Mario 64 DS, and others. They have appeared as playable characters...
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