Astatheros nourissati pair in spawning dress Photo © Ole M. Ekeberg
Keijman in 1995 pointed out that this species did conform to the standards for the Amphilophus longimanus( now Astatheros) group( although it is the most slender of the group) and thus it was transferred to this genus. Recent taxonomy revisions has assigned them to the Astatheros complex, however, studies using a phylogenetic tree has found Astatheros nourissati firmly nestled within the Theraps complex. Should we instead go back to Allgayer original description and refer to the cichlid as Theraps nourissati? As not to confuse, I will use currently accepted nomenclature and describe through the article as Astatheros. This is a medium sized fish with adult males attaining maybe as much as 25 cm, whilst females are a little smaller. A. nourisatti are characterized by a long fairly low body with strong caudal peduncle. The snout is long and the lips are large and fleshy. Unpaired fins are moderately extended with the dorsal and anal maybe reaching to the end of the caudal fin in mature males. The fish has a yellowish base colour with vertical black bars which sometimes show as a large spots especially on the middle flank of the fish. A black mark is found behind the pectoral fins and a gorgeous triangle shaped wine red flush colours the fish from behind the gill plate to behind the ventral fin. The head is yellow and the throat exhibits a copperblue colour as does the eye. All in all there is a strong resemblance to Astatheros robertsoni although A. nourissati is less blue in colour. A. robertsoni should be considered as the sister species to A. nourisatti and their range is overlapping but they have yet to be found living symaptrically. A less similar species is Astatheros rostratus which although similar in colour, it has a much longer snout it is also only found in Nicaragua a country from which A. nourisatti is absent. Astatheros nourissati is very much a rheophilic cichlid which is found in rivers of medium to strong flow although it is reported to prefer stiller areas of water within these flows, this again sets it apart from other species of the Theraps genus which very much prefer and are strongly adapted to cope with fast flowing water. The water of the habitat of this fish is always alkaline and varied from hard to very hard. This has to be remembered in captivity where acidic or soft water could do untold damage to this fish in the long term. A large tank is a must for this species, 1.5 meters being the smallest length which should be considered. Although shy in nature swimming space is appreciated and a large volume of water also gives more leeway should any pollution or water mismanagement occur.
31