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Wimpel Piranha

Catoprion mento,
CUVIER, 1819

Etymology; Greek, kata = down + Greek, prion = saw

mento, is Greek forchin, referring to the distinctive protuberance created by the curve in its banana-shaped, elongate lower jaw

 

 

From Frank Magallanes

 

Catoprion mento is monotypic and not a true piranha by ichthyologic standards. The epithet piranha is applied loosely to this species by natives because of its close appearance to the piranhas. The dietary requirements is mostly scales, however, OPEFE Wimpel piranha have been fed small guppies, cut shrimp (which they relish) and dead flies. The Wimpel teeth are everted, tubercle and arranged in a double row similar to pacus. The species is not very large, growing to about 4 ½ inches SL. All Wimpel Piranhas found in pet stores are wild caught imports that have not been bred in captivity. The range of C. mento is very limited, most come from Motto Grosso regions where it inhabits small streams.

 

Presently, there is evidence to suggest C. mento and P. denticulata are  related more genetically  than any other member of the piranha genera (Orti, 2000 et al).

 

The common name Wimpel derives from German word for the banner-like filaments that extend out from the dorsal fin. According to Bleher, Harald Schultz gave the fish that name when he discovered it.  H.R. Axelrod was with him and Axelrod misspelled the word when using it in his books as wimple. While the correct spelling of the name might not catch on, at least OPEFE readers can at least get the correction as it was originally intended by the describer (H. Schultz). The red blemish (cajete roja) is not always present on specimens nor is the extended filament. This type of ontogeny created a problem with an authority erroneously naming two other additional species as C. geryi and C. paraquayensis. The two species were erected as separate species from C. mento because of some vague descriptions pertaining to fin length, double extension of rays (similar to freshwater cichlid angelfishes genus Pterophyllum) and the lack of red-blemish on the opercle. I examined over 100 specimens of Catoprion collected from a wholesale dealer and retail outlets and found that during ontogeny those features are variable among different sized C. mento. The filament may or may not be present in juveniles as small as 2 cm SL. Those lacking the red blemish would later develop it during maturity. One other factor to take into consideration is the flowing filament often found on those called C. mento. My observation's based on 24 captive specimens found that the filament if broken off, does not develop in later stages of growth. Those that had the filament intact kept it throughout growth even extending past the caudal fin.

 

Copyright. Do not use photos outside of OPEFE without permission.

Copyright. Do not use outside of OPEFE without permission.

Copyright. Do not use outside of OPEFE without permission.

Original colored plate image of C. mento OPEFE Journal of Piranhas and Predatory Fishes, Vol. 1, 1994. Drawing by Frank Magallanes showing sexual dimorphism of male

 

IN THE AQUARIUM

 

WIMPEL PIRANHA - Scale-eater; May be kept in a small group when juvenile. Adults should be kept as individual species in home aquarium. Their other requirements includes soft, acid water; pH 5.8 to 6.2 and water temperature of 76F to 78F. A small aquarium of at least 20 gallons for one specimen should be sufficient. They require heavy planting, and soft flow of water.

 

Wimpel Piranha feeding in the wild

 

 

SEXUAL DIMORPHISM - EXAMINATION AND DISCUSSION

 

The species is sexually dimorphic (Magallanes, 1989) with the male wimpel piranha having a convex anal fin (SEE PHOTO above). Specimen examined being 7 cm SL, anal fin 2.5 cm (long) 34 rays. The count begins with the letter "I" for the first spine, then follows the count (1-14) lobed. The count continues with 15 (15 =1) to the end of the anal fin (22), for a total of 36 anal fin rays. This count was made from a photograph of C. mento found on pg. 46, Piranhas Fact and Fiction (J. R. Quinn).

 

While the above has not been authenticated, two examples (both male and female) were sent to Dr. W. L. Fink for examination (in 1993). The original type example of Catoprion mento is kept at the Paris Museum. The smallest juvenile wimpel piranha exhibit the lobed anal fin, but since it has no coloration (hyaline) one must observe closely to see the lobe. During the 3 year research of this species, it was found that only the smallest specimens of the wimpel piranha may be kept together, however as maturity develops, I found that the female wimples tending to make repeated attacks on the males, resulting in mortalities. Because of a winter power outage in 1997, many of our fishes were killed due to lack of heat and oxygenation, including the Wimpel piranhas. I hope to gather additional specimens at some later date to continue the research. Perhaps at that time the question maybe answered as to why the females are more aggressive than the males. The behavior observed here is that the females act like the arachnid, black widow spider.

 

I provided several C. mento specimens to Oregon State University (Neo-tropical Division) for DNA testing. The species was found to be a close sister to genus Pygocentrus.

 

FEEDING

 

Because the wimpel piranha has specialized teeth, it is a species that feeds principally on scales of other fishes including their own kind. According to Jeff Janovich who has researched this behavior in laboratory tests at the Department of Biology, Sweet Briar College, Sweet Briar, VA 24595. To read the research on this species, visit this link. Or read the abstract below.

 

ABSTRACT


The wimple piranha, Catoprion mento, has a narrow-range natural diet with fish scales comprising an important proportion of its total food intake. Scales are eaten throughout most of ontogeny and adults feed almost exclusively on this food source. Catoprion exhibits a novel prey capture behavior when removing scales for ingestion. Scale feeding strikes involve a high-speed, open-mouth, ramming attack where the prey is bitten to remove scales and the force of the collision knocks scales free. Unique kinematic parameters of scale-feeding strikes include a mean gape angle of nearly 120 degrees and a ;plateau' stage of prolonged maximum displacement for cranial elevation and opercular expansion. When feeding on live fish or loose scales, Catoprion performs a typical ram/suction attack that is modulated according to the elusiveness of the prey. Captures of elusive fish elicit faster strikes with greater displacement of cranial elements than do attacks on loose scales sinking in the water column. Despite its specialized diet and suite of anatomical characters, functional versatility in feeding behavior has not been reduced in Catoprion, as predicted by many analogous studies in functional morphology. On the contrary, the behavioral repertoire of Catoprion has been broadened by the addition of a novel behavior for scale feeding. 

 

In my past conversations with Jeff, we have both marveled at this species specialized nature. It is my hope that genus Pygocentrus is also examined in terms of bite strength.

 

SYNONYMS

DISTRIBUTION

 

Amazon, Orinoco, Essequibo and upper Paraguay River basins: Bolivia, Brazil, Colombia, Guyana and Venezuela; Drainage: Amazon, Paraguay, Vichada, Meta, Curua-Una, Negro, Trombetas, Caures, Pitinga, Uatuma, Tapajos, Jau, Essequibo, Mamore-Madiera, Apure/Orinoco, Moruka River, Gurico, Capanaparo, Ocamo, Mavaca, Guariquito, Llanos E, Branco, Caura, Rio Meta, Upper Orinoco River, Orinoco river.

 

Contributors and Advisors:

REFERENCES

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Created: April 10, 1994

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UPDATED: 12/26/2011