The discovery of both of these characteristics in Lithogenes suggests to ichthyologists Scott Schaefer of the American Museum of Natural History and Francisco Provenzano of the Universidad Central de Venezuela that the common ancestor of the Loricariidae and Astroblepidae probably could grasp and climb rocks with its tail and mouth.
It took years to pin down where the fish was found, but the team collected L. wahari after several trips further and further into the headwaters of the Río Cuao, a tributary of the Río Orinoco. They literally picked 84 specimens off of rocks.
Well, this is how it looks... Not so pleasant but interesting!
Ugly Animals - Climbing Fish