Freshwater Barracuda (Ctenolucius hujeta)
Other common names for this fish: Rocket Gar, Hujeta Gar, Gar Characin, Slant Nosed Gar, South American Freshwater Needlefish.
Size is currently about 2-3 inches.
These fish do well in pairs or groups and tend to dwell on the upper levels of the tank. Be sure to house them with fish no smaller than them as they will inevitably become eaten by the Gar.
A well secured cover or lid is required as they can jump. They aren't brackish water fish though a tad bit of salt will be good for them.