Before there was a "golden wonder" killifish (the modern version, A. lineatus) there was a "golden Panchax" in older aquarium literature. This fish, the only freshwater fish found in the Seychelles island is found nowhere else. A colony was transplanted to Zanzibar where it endures because it can tolerate freezing to well over 100 degrees F, full marine or fresh water or anything in between. They will eat anything and get along with fish as large or larger than them although some will fight. Paul Loiselle claims they're the meanest fish in the genus, and he should know, nobody has more experience with that genus.
Females can be easily recognized by the dark spot in the dorsal fin. In specimens ready to spawn the scales on the back ruffle up. This phenomenon is unique among all the fish species known so far.
Current thinking is this or something like it is ancestral to nearly all killifish.