> ...researchers also found that the [wet-rock-climbing] bumblebee catfish isn’t alone. Three other fish species were also scaling the waterfalls alongside the bumblebee catfish, and none of the four had ever been documented climbing before.
Being fish, this sounds like convergent evolution. (Vs. learned behaviors.)
They seem to all be fish that live in fairly fast flowing waters, my guess was they are able to use rocks+suction system to hold in place for stuff, they probably don't even really have a concept they are climbing a wall, it could just feel like a particularly intense rapid?
I would say that these are not sharply defined categories, there is more a like a smooth continuum from "fast-flowing stream" to "rapids" to "small waterfall" etc.
And this is a good environment in which evolution could progressively improve rock-holding and climbing ability.
I'd figure it's slightly more complex than that (see details in article) - but I bet you're right about both the evolutionary basis for the behavior pattern, and for having bodies well-adapted to doing it.
Being fish, this sounds like convergent evolution. (Vs. learned behaviors.)