Gloop

A Gloop is a smaller relative of Fangfish that appears only in Donkey Kong Land. They appear primarily in Kremlantis, but also make appearances in bonus rooms in other worlds. They have an appearance similar to a. They slowly swim back and forth horizontally, and as such, they are not actively aggressive. However, they commonly appear in pairs in narrow passageways, making them more difficult to get past. They also tend to swim near pits where Flappers are.

Trivia

 * In a Donkey Kong Land preview in Nintendo Power, it can be seen that instead of Gloop, the game was originally to include a much larger fish known as "Pucka," while Fangfish was instead known as "Pucka Jr." Pucka has similar fin position to Gloop, but otherwise bears little resemblance.
 * In the game's official Japanese guide, Gloop conspicuously lacks its own artwork, unlike the other enemies, instead simply using a screenshot.

Reference
Gloop