Cheep-Cheep
Cheep-Cheeps are fish that made their first appearance in Super Mario Bros. in the underwater levels, just like Bloopers. They are pretty annoying, but can be taken out with a fireball. In some levels Cheep-Cheeps jump off from the bottom of the screen creating random obstacles. In Super Mario Bros. 3 they act the same but can also jump out of water and lava.
Cheep-Cheeps are also found in many Mario Kart courses. They are found in Super Mario Sunshine as well, in places with water, like Ricco Harbor and Noki Bay. Even though most of the time they are flailing out of water, they cause you to spin out when touching them. They can be defeated with FLUDD, but will reappear almost instantly. Yoshis can turn them into platforms by spraying them with certain fruit juice.
Although they were not included in the credits in Super Mario World, they posed a numerous threat as the white slow moving fish underwater and in floating bubbles.
In Paper Mario: The Thousand Year Door, some have jobs like Stewart, the Glitzville blimp conductor. It is strange how they can live out of the water, although some people count those Cheep-Cheeps as a sub-species of the kind that live in water.
Cheep-Cheeps have their own language, also called "Cheep-Cheep".