SCOTCAT.COM
your internet guide to all things catfish
FACTSHEETS: January 2021 - no. 295
Imparfinis stictonotus (Fowler, 1940) |
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.
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Location near Puerto Maldonado, Peru |
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Distrbution: Ucayali, Mamoré/Madeira and Paraguay River basins. Type Locality: Todos Santos, Rio Chapare, Bolivia. |
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Madeira River basin |
The Madeira River is a major waterway in South America. It is estimated to be 1,450 km (900 mi) in length, while the Madeira-Mamoré is estimated near 3,250 km (2,020 mi)[2] or 3380 km in length depending on the measuring party and their methods. The Madeira is the biggest tributary of the Amazon, accounting for about 15% of the water in the basin. A map from Emanuel Bowen in 1747, held by the David Rumsey Map Collection, refers to the Madeira by the pre-colonial, indigenous name Cuyari.
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Common Name: |
Shrimp Catfish |
Synonyms: |
Nannorhamdia stictonotus |
Family: |
Heptapteridae |
Subfamily: |
- |
Distribution: |
South America: Ucayali, Mamoré/Madeira and Paraguay River basins. Type locality: Todos Santos, Rio Chapare, Bolivia. |
Size: |
5.0cm. (2ins) |
Temp: |
24-28°C (75-83°F) |
p.H. |
6.0-7.0. |
Characteristics |
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. |
Colouration |
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. |
Aquarium Care & Compatibility |
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. |
Reproduction |
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. |
Sexual differences |
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. |
Diet |
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. |
Glossary of Terms |
Lateral
line: A sensory line, along the sides
of the body. |
Etymology |
Imparfinis: Latin, impar = unequal + Greek, finis, pinna = wing, fin (Pertaining to the longer top lobe of the caudal fin). |
References |
Froese,
R. and D. Pauly.
Editors. 2009. FishBase. World Wide Web electronic
publication. www.fishbase.org, version (05/2011).
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Photo Credits |
© Allan
James @
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