The Kotso (Paretroplus petiti) is a species of cichlid in the family Cichlidae. It is endemic northwestern Madagascar. Currently rated as data deficient by the IUCN, this species is virtually unknown. The only known specimen is a juvenile that was collected more than 80 years ago. It is not entirely clear where it was collected, but likely from the Maintimaso River or Lake Ambanja, which both are part of the Betsiboka River drainage. Erroneously, the name Paretroplus petiti has often been applied to members of a different species, Paretroplus dambabe.