That is one of the cachorros, probably a Acestrorhychus grandoculus, but possibly a A. pantaniero. It has a slightly damaged snout which is pretty common. Bothe of these get a bit bigger than ten inches and are a lot less spooky in a planted tank with floating leaves they can lurk under, They won't bother other fish that are to big to eat but will eat fish at least 1/2 their own size, they adapt well to standard tropical aquarium conditions but are very hard if not impossible to wean off live food. They prefer fish but take live crickets, earthworms and shrimp or small crayfish. They tend to be pricey, I have only seen facatus, Isaline's, and grandoculus for sale but other types like altus and pantaniero do sometimes show up. Congratulations.