Nematode specimens of two Procamallanus species, P. (Procamallanus) planoratus Kulkarni, 1935 and P. (Spirocamallanus) guttatusi (Andrade-Salas, Pineda-Lopez et Garcia-Magana, 1994), were collected from broadhead catfish Clarias macrocephalus (Clariidae, Siluriformes) and orange-spotted spinefoot Siganus guttatus (Siganidae, Perciformes), respectively, from the Philippines. Their examination, including scanning electron microscopy (SEM) that was used for the first time in these species, made it possible to obtain new data on their morphology, to elucidate their systematic status, and to redescribe them. Procamallanus clarius Ali, 1957 and P. heteropneustus Ali, 1957 are considered junior synonyms of P. planoratus. Heavy P. guttatusi infections found in Siganus guttatus reared in Fish Hatchery of SEAFDEC AQD in Tigbauan, Iloilo indicate that this parasite may have negative implications on the health condition of fish in culture.