The slender freshwater needlefish from South America are much sought for by specialists. Many years only one species was mentioned in the aquarium literature, namely Potamorrhaphis guianensis. This species really exists and is said to be fairly wide spread in South America. But it seems that the needlefish we obtain from Peru currently belong to another species.
Currently, four Potamorrhaphis species are recognized, and after a thorough review of the literature, it seems most likely to us that our Peruvian specimens belong to the species P. labiata. The main difference from P. guianensis, which is mentioned in the scientific literature, is very difficult to discern in live fish; it concerns the labial membrane located at the lower base of the mouth, which in P. labiata is large and crescent-shaped. This protrusion is absent in P. guianensis; in this species, the lower lip membrane is narrow and inconspicuous. In our recent photo session, we managed to capture a snapshot in which the crescent-shaped lower lip membrane is clearly visible. We have marked it with an arrow in the image.
Potamorrhaphis labiata grows to about 18 cm in length. These fish get along very well with one another. During the acclimation period, care must be taken to ensure the fish do not get startled; otherwise, they may seriously injure the tips of their mouths. Minor injuries of this kind are, however, unavoidable and heal well.
As strictly fish-eating species, Potamorrhaphis must initially be fed live fish, but acclimated specimens will also take frozen fish from tweezers. Water parameters are irrelevant for their care; any water suitable for drinking is appropriate. The water temperature can range from 22 to 28°C. And do we really need to mention that these specialized surface-feeding fish are excellent jumpers and that the tank must therefore be completely covered? I don’t think so…
For our customers: these fish are listed under code 281544 on our inventory list. Please note that we supply exclusively to wholesalers.
Literature:
Sant’Anna, V. B., M. L. S. Delapieve & R. E. Reis (2012): A new species of Potamorrhaphis (Beloniformes: Belonidae) from the Amazon basin. Copeia 2012 (no. 4): 663-669.
Text & Photos: Frank Schäfer
