A new haploporid trematode, Culuwiya cichlidorum n. sp., is described from the intestine of the black-belt cichlid Vieja maculicauda (=Cichlasoma maculicauda (Regan)) from the Atlantic coast of Nicaragua. It differs from congeneric species from freshwater and estuarine mugilid, cichlid, and gobiid fishes, previously placed to Saccocoelioides Szidat, 1954, and Carassotrema Park, 1938, in possessing the intestinal ceca reaching up to the posterior half of the testis and a bipartite, swollen external seminal vesicle. The new species also is characterized by a small, pyriform body, a well-developed prepharynx, a large pharynx, extensive vitelline follicles, confluent posterior to the testis that is situated near the posterior extremity, a uterus limited to the pretesticular and postacetabular region, and few, but relatively large, eggs (67–81 × 36–47 μm, i.e., about 12–14% of the body length) and miracidia without eye-spots. Culuwiya cichlidorum is also reported from Tomocichla tuba (Meek) in Nicaragua and species of Cichlasoma, Herichthys, Oreochromis, Parachromis, Petenia, Theraps, and Vieja from Mexico.