Also known as "Dwarf Orange" and "Orange" Gularis; nobody knows where this form originates having said to be found in a pet shop there is zero evidence it's wild caught or tank bred, we simply know nothing. It may be a naturally occurring population - somewhere or it might be line bred in aquaria.
It appeared in the 1960s and was available thorough AKA in the early 1970s and found in AKA conventions up until around the early 1990s, when Szafreneck remained the sole exhibitor of the strain. Since the mid 1990s what we see as "dwarf red" is a different fish, the "old" dwarf rd has rounded caudal fin tips, the nw one is larger and has pointed fin tops. I've heard people crossed Szafreneck's strain (referring to is as "German Dwarf Red") with Niger Deltas with orange pecs and this perhaps represents a "US Dwarf Orange" as counterpoint to the German one.