What is this tropical sucker fish called?

Please provide me with more information about the tropical sucker fish you're asking about.

For example:

* A description of the fish: Color, size, shape, any unique features.

* Where you saw it: In a tank, in the wild, in a picture?

* Any other information you have: Did it have a specific name on a tag, or was it in a specific exhibit?

The more information you can give me, the better I can help you identify the fish.