I agree, they are so similar, and geographic ranges are so close, the DNA sharing is probalby almost indistinguishable, yet the water paramaters they have evolved to live in are quite opposite.
kind of reminds me of how similar Andinoacara pulcher from Colombia (pH 7 (natural form), and A coeruleopunctatus (pH above 8) from Panama , are difficult to tell apart,
the only difference being the Panamanians cichlids evolved abilty to tolerate higher pH and mineral content than their soft water Colombians
But not only cichlids, the way Sturisomatichthys whiptail cats, S panamense (pH 8) in Panama, and Sturisomatichthys species from the soft waterrs of Colombia, pH 7 and lower.

and Chaetostoma fischeri of Panama (pH 8 and higher)and C palmeri of Colombia , pH 6.
or the Ctenolucius beanii of Panama compared (pH 8*) to Ctenolucius hujeta of Colombia pH 7 and much more acidic.
