Bub (Super Mario 64)
From the Super Mario Wiki
Bubs are small, slow-moving orange fish that act similar to Cheep-Cheeps, found in the course Dire, Dire Docks in Super Mario 64. Bubs will follow Mario when he swims, but they don't tend to attack the plumber. However, if Mario touches a Bub, he will be damaged, thus losing health. They are possibly juvenile Bubbas, a gigantic version of Bub that wears sunglasses, but was replaced by Big Bertha in the remake. In Super Mario 64 DS, Cheep-Cheeps also replace Bubs.