500px provided description: Xiphophorus continens, not yet completely full-grown, I think. At least I would expect a mini-"sword"of 1mm or so at the male's tail. This is the dominant male and the coloration is much more clearly developed as compared to the other male.

Forgive the mediocre image quality... [#fish ,#aquarium ,#freshwater ,#zierfisch ,#ornamental fish ,#Aquarium ,#Fisch ,#S??wasser ,#Zierfisch ,#El Quince Swordfish ,#xiphophorus continens ,#lebendgeb?rende zierfische ,#wildform ,#el quince schwerttr?ger ,#nachzucht ,#livebearer ,#lebendgeb?rende zahnkarpfen ,#lebendgebarende zahnkarpfen ,#poeciliidae]