I find in interesting that while the Characins, Mullet, Molly and Gobies such as Awaous species in Costa Rica are the same in Panama, the cichlid species are quite different, only 500 miles apart.
Above Brycon guatamalemsis, below Awaous banana
Agnostomus mmonticola (mountain mullet)
Yet the cichlid species found here in eastern Panama, are quite different.
Above Darienheros calobrensis, below, Isthmoheros tuyrensus
Below Geophagus crassilabris
Below Andinoacara coeruleopunctatus
Below typical Poecilia gilli (molly)