Apistogramma payaminonis Kullander, 1986 is redescribed based on the only two type specimens available, and two new, closely-related Apistogramma species are described from Peru. Data from the original description of A. payaminonis are supplemented with information on phenotypic appearance, which is important for differentiating the taxon from several other species discovered in the last few years. Apistogramma feconat sp. n. is described from four specimens from the catchment of the Río Tigre, Loreto; information on its ecology, biology, and current conservation status is summarised. Apistogramma wolli sp. n. is described from six specimens from the catchment of the Napo river, Loreto, close to the Peru-Ecuador border; information on its ecology and biology is sparse. Both newly described species are representatives of the Apistogramma nijsseni complex that live in small forest streams influenced by blackwater. Information on differentiating females of some members of this group of related species is presented. At present no clear information based on voucher specimens is available regarding the possible distribution of the two species in Ecuador. Man-made environmental hazards potentially endangering the aquatic fauna in the western catchment of the Río Marañón and the Rio Amazonas, between their tributaries the Rio Pastaza and the Rio Napo, are discussed.

Apistogramma feconat sp. n., Apistogramma wolli sp. n., Apistogramma-nijsseni-complex, systematics, ichthyology, freshwater, ecology, new taxa, endangered species.