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he first factsheet of 2021, which we all hope will be a lot better than the previous year provides me with a memory of way back in April 2017 when I first embarked on a collecting trip to the Rio Madre De Dios area of Peru with the Eco Travel Company, Go Wild Peru, with the owner Ian Fuller from CorydorasWorld.com along with my companions, U.K. aquarists Steven Grant (Catfishes of the World), Richard Smith, and Jamie Horne. This will maybe push me to write a further article on this special trip sometime in the future.

Imparfinis stictonotus - wild caught specimen

One of the most abundant catfish species we came across on our 14 day trip was our factsheet of the month subject, the "Shrimp Catfish", Imparfinis stictonotus. This member of the Heptapteridae family is known from its type locality Todos Santos, Rio Chapare, in Bolivia and the area of the Madeira River basin which is close and covers the south eastern parts of Peru. This species is very like Imparfinis pseudonemacheir and I'm yet to be convinced that this is not the same species although the type locality for this is further north in Venezuela and covers the Orinoco and Ucayali River basins. As far as I am aware Imparfinis pseudonemacheir could end up as a synoynm of Imparfinis stictonotus in the future. The image above shows a freshly caught specimen from near the city of Puerto Maldonado and below an aquarium specimen showing a dark pattern, but the wild caught specimen could be showing a fright pattern.

Imparfinis stictonotus - aquarium specimen

The map below shows the area of capture in Peru and the type locality in Bolivia. A note on the water parameters from this location was a high p.H. of 8.2 and a temperature of 25.8C (78.4F) which considering the large area covered for this species indicates that it is very hardy little catfish. We found a lot of specimens on the sides under vegetation in small streams with every sweep of our nets.

The Imparfinis family was diagnosed by osteological characters by Bockmann 1998 which are not easily observed externally. The whole family can be found in a vast area of South America in the coastal drainages of Guineas, Amazon, Orinoco, Sáo Francisco, and San Juan basins, Paraná, Uruguay, and Paraguay basins; and along eastern Brazilian coastal basins. The genus name of Imparfinis ; Latin, impar = unequal + Greek, finis, pinna = wing, fin refers to the longer top lobe in the caudal fin which you can see in the image above.

This genera has 22 described species recorded with the types species being Imparfinis piperatus Eigenmann & Norris, 1900, with one (I. lineatus) in Central America. Most of them don't grow too big and can be housed with most fish as long as they are not too small with the danger of them being eaten.

Location near Puerto Maldonado, Peru

Distrbution: Ucayali, Mamoré/Madeira and Paraguay River basins. Type Locality: Todos Santos, Rio Chapare, Bolivia.

Shrimp Catfish

Nannorhamdia stictonotus

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South America: Ucayali, Mamoré/Madeira and Paraguay River basins. Type locality: Todos Santos, Rio Chapare, Bolivia.

5.0cm. (2ins)

24-28°C (75-83°F)

Genera description: Moderately elongate body, oval in cross section through the dorsal fin origin; snout convex in dorsal view; mouth subterminal; eye of medium size, dorsolateral, with free margin; premaxillary tooth plate wide, not bearing projection at posterolateral angle; maxillary barbel moderately long its extremity usually reaching the end of the pectoral fin. Pectoral fins usually with 8-10 branched rays; first dorsal fin ray (spinelet) absent. Anal fin short having 11-15 rays; caudal fin deeply forked. Lateral line usually continues to caudal peduncle.

Brown to greyish, with 7 transverse dark bars on back; one immediately posterier to head, one in front of dorsal fin origin, one on postereir half of dorsal fin base, one between dorsal fin base and adipose fin base, one on adipose fin origin, one on adipose fin end and one on base of procurrent rays of caudal fin. A lateral stripe is normally present.

Peaceful towards conspecifics but territorial with its own kind. Provide a moderate sized aquarium with hiding places such as bogwood, rockwork and plants. A good water flow is recommended with good aeration and filtration. They tend to bury themselves in the substrate so sand on the bottom would be the substrate of choice.

These catfishes are externally fertilising and are not known to practice parental care. Amaral et al. (1998) described reproductive females of a member of the Heptaperidae family, namely the species Pimelodella pappenheimi which was burying in the clay palsades of the sediments of a small coastal stream in southern Brazil, a behavior adaptation to protect the offspring from being washed away.

Sex dimorphism is not present or scarcely developed in heptapterids. Juveniles of most species are miniature replicas of the adults. There are few data on the reproductive cycle of heptapterids, probably due to its reduced importance in commercial fisheries and aquarium imports.

In their natural habitat they will be found solitary and active during the night hunting for insect larvae turning over the sand/gravel substrate in seach of prey. In the aquarium they can be fed, live, frozen and flake foods.

Lateral line: A sensory line, along the sides of the body.
Caudal fin: Tail
Caudal peduncle: The narrow part of a fish's body to which the caudal or tail fin is attached.
Dorsal fin: The primary rayed fin(s) on top of the body.
Pectoral: The paired fins just behind the head.
Maxillary barbels: Pertaining to the upper jaw. (maxillary barbels).

Imparfinis: Latin, impar = unequal + Greek, finis, pinna = wing, fin (Pertaining to the longer top lobe of the caudal fin).

Froese, R. and D. Pauly. Editors. 2009. FishBase. World Wide Web electronic publication. www.fishbase.org, version (05/2011).
Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Sleen, van der Peter and Albert, S. James; Field guide of the Amazon, Orinoco & Guianas. Princeton University Press, Princeton and Oxford. 2018.
amazonwaters.org
Grant, Steven. pers comm.

Photo Credits

© Allan James @
© Stuart Brown
© Jamie Horne
Map: Google maps 2020
Map: amazonwaters.org ©2020 Wildlife Conservation Society.
amazonwaters.org/terms-of-use