Pygocentrus cariba Humboldt, in Humboldt and Valenciennes

TRUE CARIBE

also called Caribe Capa Burro or Caribe Colorado
Pygocentrus cariba
Humboldt, in Humboldt and Valenciennes, 1821

This species have always fascinated me and their natural beauty is one today, that still holds my attention. My first contact with the species was a TFH Publications booklet by Harald Schultz on Piranhas (1964). There inside the pages, was a photograph of this species under the erroneous scientific name caption of Serrasalmus nattereri. The photograph of the fish seen below still remains the best photographic representative of this species. It was only a matter of time before I was able to secure my first live specimen of this species in 1973. The fish I purchased was approximately 6 inches total length. So now, let's discuss this species some more and what we have learned in the last few years.

Pygocentrus cariba is characterized by four *supraneurals and a prominent black humeral spot on the flank (FINK, 1993).

[*Supraneurals are small bones that are between the neural spines of the vertebrae, anterior of the dorsal fin. They may vary in number, depending on the position of the dorsal fin (Weitzman, 1962)]

The state of the systemic of Pygocentrus is typical of many Neotropical groups. Only three of the nominal species were described in this century (20th), and in some cases the type specimens have been lost (FINK, 1993). There was speculation that Pygocentrus nattereri could be a sister to P. cariba. In most of the features that allow differentiation among the species, P. nattereri is the most similar to P. cariba (FINK, 1993). Current data today has shown that P. nattereri is indeed distinctive from P. cariba. Pygocentrus cariba forms a unique clade in having a prominent humeral spot behind the gill cover on the flank. The dark humeral spot may be absent on some specimens and can cause confusion among hobbyist who wonder if they might have a different species of piranha. However some captive specimens may lose this blemish for a number of reason's including poor diet and water conditions. Age seems to be the biggest factor in loss. This species is likely the one with the worst publicity of the species placed in genus Pygocentrus. Evidence for this observation is discussed. When in breeding condition body, fins, turn totally black. P. cariba (NICO and TAPHORN, 1986) also called caribe capa burro (donkey castrator) is found often near bird roosts. Large birds feed their young fish. The remains of these fish sometimes fall into the water becoming a meal for the capa burro waiting below. The small birds learning to move around the nest and branches sometimes fall into the water too. This availability of food has conditioned the piranhas to attack anything that falls into the waters from these trees. This makes the water very dangerous for any animal entering it, especially during the dry season when food is scarce. Piranhas during the dry season are trapped into small pockets of water and become very hungry. However, reports from researchers in the field who have entered these waters report no active aggressive behavior. Still, caution is required of any animal that has been conditioned to a ready food source and there are indeed reports of the fish biting humans in certain fishing areas. Again, this is the result of conditioned feeding of entrails tossed into the waters.

There are some species of P. nattereri from the Rio Araguaia that have bright red bellies and clear eyes, but these are different species from P. cariba and lack the supraneurals that P. cariba possesses. P. cariba form the second largest sized Pygocentrus next to P. piraya. I also consider them one of the prettiest to keep in the home aquarium and most colorful.

According to Dr. William L. Fink (1993), Pygocentrus cariba either under the name albus or caribe, has been long considered a synonym of Serrasalmus rhombeus (see Eigenmann, 1915) but was originally described as having a dark eye, rather than red as in S. rhombeus. Most of the written description does not seem to apply to rhombeus nor does the figure resemble that species. However, even though no type specimen of cariba exists, the plate and description in Humboldt and Valenciennes include sufficient detail to suggest that cariba, is a Pygocentrus. Most of the original description of cariba is a mélange of piranha lore which includes information on several species. But it is clear from the main theme of that the description from the author was attempting to describe a common, aggressive piranha of the Rio Orinoco.

Pygocentrus certainly fits that characterization, and there is reasonable justification for use of cariba for the Venezuelan Pygocentrus.

Potentially Dangerous to Humans - May be kept as a group, some moralities reported so caution should be exercised when putting several individuals together in the home aquarium. Most of the injuries, according to reports, occur when the fish is juvenile or at sub-adult size. The problem of keeping the species together seems to center on the size differences and the size of the aquarium being used. Also inexperience in keeping the species in a suitable environment is a monumental problem. Hobbyist generally put large fish into aquariums they can afford, which are usually small sized aquariums (55 gallons). Another problem is their perception of the animal based on myth and legend of the species. So overfeeding and poor conditions are the norm for those that actually know little about the species requirements. They believe the animal must be fed live food and that is not necessary, contrary to published reports, in the home aquarium.

Often seen in National Geographic Society television specials feeding on young birds that fall in the water! Strongly disliked by ranchers because of the fish reputation of mutilating cattle's underside (bellies) while crossing rivers or lips while drinking water. Majority of stories surrounding this species are suspect based on actual contrary evidence. But they can be dangerous to handle if you are fishing for them and get careless. So caution is required when moving the fish with a net from the aquarium. They can easily bite through it, so use a bucket under the net should the fish fall through. A flopping on the floor caribe is a dangerous fish to hands or feet! The aquarium size that is recommended for a single P. cariba is 50 U.S. gallons, for additional specimens larger aquariums are recommended. Water temperature should be maintained at approximately 78-82F and live plants should be used. P. cariba are known to eat them, so a good supply of hardy plants is also recommended.

Below is an example of their feeding frenzy, photographed by Eduardo Paiva. He went to Hato El Frio in the Venezuelan Llanos in April 13 and 14 and pictured a group of Pygocentrus cariba eating a big piece of meat that was offered to them in Rio Caño Guaritico.

Juveniles and adults collected in Rio Apuré of Venezuela (UMMZ 214742), dorsal and lateral parts of body from black humeral spot to anal-fin origin silvery gray. Abdomen from lateral spot to anal-fin origin red to reddish-orange. Most of head gray, suffused with orange or red, especially posterior and ventrally. Eye silvery, with black pigments above and below iris. Lower jaw dark anterior, posterior the same red or orange as the abdomen, pectoral and pelvic fins, red through orange. Dorsal fin dark grayish-black. Adipose fin black proximally, often some hyaline area distally. Caudal fin dark grayish-black, with a pale subterminal band or posterior border. Anal fin is black, proximally in the area of small scales on the fin and with black pigment scattered along distal margin; otherwise, fin red or red-orange. Large juveniles to adults: Based on specimens between about 80-120 mm SL (UMMZ 211299 from the lower Orinoco) much of the color pattern remains similar to that of juveniles. The distinctive changes noted is the loss of the caudal spot, a pale belly compared with the dorsum in larger specimens, and the presence of a humeral blotch just posterior to the opercle. The black blotch on the shoulder reaches dorsally nearly to the dorsal border of the opercular opening and ventrally nearly to the pectoral fin in some specimens. The anterior border of the blotch is the cleithrum (Fink 1993). Specimens at around 80 mm are still densely spotted. In larger specimens, body spotting is no longer present. Very large adults are darker, to the point that the shoulder blotch is not visible. Breeding adults give the appearance of a "black" piranha in coloration.The extent and hue of the belly coloration is somewhat variable individually, geographically, and depending on color of the water in which the fish lives (FINK, 1993). Pygocentrus cariba is widely distributed in the Rio Orinoco basin lowlands, in Columbia and Venezuela. It is listed among record species, with a 1-pound 4-ounce fish being the largest caught (source: Field and Stream 2002).

The teeth of Pygocentrus cariba are broad, serrated, tricuspid and razor sharp. These teeth are used for slicing chunks of fish. These teeth are backup by strong musculature that have enough force with combination of the teeth to clip off a finger or toe! A medium sized P. cariba (8 inch specimen) can have teeth as long as 7 mm TL or larger depending on the overall size of the animal.

P. cariba can range up to 38 cm (15 inches) TL, but usually range up to 30 cm (12 inches) and weigh up to 1 kg (Taphorn 1992). They have very high foreheads and a bulldog-like face, which makes them look considerably large.

Orinoco Basin, widely distributed in the Orinoco River basin lowlands and tributaries into Columbia.

Drainage: Llanos, Orinoco, Cinaruco- Orinoco, Apure/Orinoco, Cano Igues Portuguesa, Portuguesa-Apure, Orinoco Delta, Guariquito, Uracoa, Medio Rio Orinoco, Caura, Capanaparo, Ventuari, Alto Orinoco, Ocamo, Cojedes, Rio Payara.

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