Catfish of the Month Right Arrow September 2014

Nannoglanis fasciatus   Boulenger, 1887

Article © Rupert Collins, uploaded November 04, 2014.

Rupert Collins is, to many, living the dream. He writes this months CotM article from the heart of the Brazilian Amazon and in it he recounts the finding of a species that is new to, I suspect, almost all of us. I am certainly not embarrassed to say it was unfamiliar to me. Many of his forum posts and articles have further detailed his ichthyological ventures around the globe and, to this day, meeting Rupert years ago and visiting him at home before he set off on this path has lived long and fresh in the memory. I'm delighted to introduce another "catfish guy's catfish" article this month.

Heiko Bleher once famously proclaimed to have never misidentified a fish. Well, I've misidentified many, and the fish in question here is no exception. In fact, I was so profoundly mistaken that I did not just get the species and genus incorrect, I got the entire family wrong. In my defence, I was peering into a murky plastic bag, and my misidentification is in good company, for it was also described by Boulenger in 1887 in the family for which I suspected it to belong: the Trichomycteridae. Nowadays, Nannoglanis fasciatus resides in the Heptapteridae, a family poorly known to science, and even more poorly known in the aquarium hobby. This is a real shame though, as many heptapterids are small, unassuming, and probably well suited to life in the aquarium.

Nannoglanis fasciatus, both species and genus, were described on the basis of two specimens collected in the Napo drainage of eastern Ecuador by a Mr. C. Buckley in 1880 (these exact two specimens, the syntypes, are shown in Fig. 1). They lacked any more specific information than this, and almost nothing has been written about them since. They appear to be poorly represented in museum collections too, with only a couple of other reports from collections also made in Ecuador. Nannoglanis is currently a monotypic genus, and can be distinguished superficially from other heptapterids by a colouration pattern comprising of four black-bordered saddles along the body.

My encounter with these overlooked fishes took place on a recent visit to the Rio Japurá in Brazil, a river also known as the Caquetá once you reach Colombia. We collected the catfishes in shallow, clearwater forest streams (igarapés) around three metres wide. Water temperature was 24.6°C. The catfishes were found among the gravel riffles between pools (Fig. 2.), and appeared relatively abundant, with up to five individuals being captured in a single sweep deep into the gravel. Water depth over these gravel riffles was usually less than 30 centimetres, and when observed, the catfishes blended in perfectly among the small stones and roots. With a colouration remarkably similar to those of Asian akysid and sisorid catfishes such as Akysis and Pseudolaguvia, it is probable that this patterning arose due to their similar environmental conditions. The streams were also host to numerous other fishes, including Crenicichla, Apistogramma, Nannostomus, Hemigrammus, Tyttocharax, Carnegiella, Moenkhausia, Steatogenys, Gymnotus, Helogenys, Tatia, Auchenipterichthys, Ituglanis, and two other heptapterids (Chasmocranus and Nemuroglanis).

Nannoglanis fasciatus would likely make an ideal aquarium inhabitant, especially for those experienced in the care of akysids, balitorids or other Asian hill-stream fishes. Unfortunately, however, the species is unlikely to appear on import lists. Local villagers do occasionally collect and sell ornamentals across the border to Colombian traders, but this is limited to the higher value fishes such as stingrays. Oddballs like Nannoglanis remain, unfortunately, overlooked.

  • Nannoglanis syntypesFig. 1. The two specimens collected from Ecuador by C. Buckley in 1880.
  • Nannoglanis habitatFig. 2. The habitat of Nannoglanis fasciatus: gravel riffles in a forest stream.
  • References:
  • Boulenger, G. A. (1887). An account of the fishes collected by Mr. C. Buckley in eastern Ecuador. Proceedings of the Zoological Society of London 1887 (pt 2): 274-283.
  • Bockmann, F. A. and Guazzelli, G. M. (2003). Family Heptapteridae. In: Reis, R.E., Kullander, S.O. and Ferraris, C.J. (Eds.) Check List of the Freshwater Fishes of South and Central America. Edipucrs, Porto Alegre, RS, Brasil.

Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

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