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C. macropterus, doing laps of the aquarium in expectation of food

 

Some aquarists know this phenomenon: The keeping of a certain fish species binds one in such a way that one turns to it again after many years of occupation with other ornamental fish.

The catfish species described here we already had kept in the middle of the 1980s, and after approximately two decades we returned to it again to its keeping, whereby the procurement of one specimen brought us together and led to an active exchange of experiences.

C. macropterus, doing laps of the aquarium in expectation of food.

Species description
The genus Calophysus belongs to the large family of the Pimelodidae and is monotypical, (consists only of the one species). The German description “Gefleckter Silberantennenwels” (meaning “spotted silver-coloured Pimelodus”) describes the colouring of this species which is far spread in the northern parts of South America and particularly in the Amazon basin. On its long stretched silver-grey body it exhibits a multiplicity of irregular dark points. By means of this mottling there can obviously be different habitat variants that are about. Above all, the bluish resplendent gloss intensifies, starting from a length of 30 centimetres making this a true eye catcher.

In its body form and patterning C. macropterus reminds us of two further catfish species of South America: Aguarunichthys torosus (German: Stierantennenwels), which is however spotted up to the underneath of the belly, and the even more rarely introduced Platynematichthys notatus, whose impressive extended dorsal fin ray makes it unmistakable. Also C. macropterus is not often seen in the trade, however it is now and is offered by specialist dealers, who specialise in the import of predatory species. Particularly young animals are to be had with approximately 40 euro, which is comparatively low priced.

Keeping
When stressed this species is quite oxygen needy, and it indicates this by an increased respiration rate, so moved specimens need rather a long time until they have acclimatised themselves, therefore the keeper should pay attention to sufficient ventilation. Besides this, it is durable, and with good filtering a temperature of around 24 degrees Celsius and otherwise "normal" water parameters, it is easily kept.

 

In its natural habitat C. macropterus will get to a maximum length of 60 centimetres, in the aquarium it reaches 40 to 50 centimetres. Since it is no ambush predator but a more active species, tanks that are to be used should, if at all possible, be not less than two meters in length and a minimum depth of 70, or better, 80 centimetres.

This catfish feels well if it has a sufficient swimming area left to it. In the rear of the aquarium, well secured stone structures or durable solitary plants should be present and roots or large stones as resting places, then a hiding place, into which the animal can retire itself completely, is not necessary.

Calophysus macropterus adult in profile - with its barbles this catfish can smell excellently.

Aquarium observations
C. macropterus proves in the aquarium that it can be relatively peaceful. Generally one can find it at its favourite place, to which at the same time also means that you can use this as an observation post, particularly since the catfish leans on its ventral fins and erects the upper part of its body. In nature predominantly with entrance of dawn they are active. Aquarium specimen are also out during the day in this way. Separately kept they seem to do quite well.

 

 

 

The high-sensitive barbles leads the animal to the piece of trout lying on the ground.

Even for the viewer it is impressive: First finding the prey in principle takes place not by means of visual contact, but owing to the forward placed barbles it guides the animal even with weak smelling traces, and as also in nature in cloudy water, still leading to the food.

The species is not choosey with the selection of its food and besides live foods such as earth worms it also gladly takes shrimps or fish filets, even food sticks or Forelli pellets are eaten. In nature these flexible predators are even predominantly nourishing themselves on carrion, therefore comes the English description of "Vulture Catfish". So it is not surprising that the muzzle of C. macropterus with its strong jaws and the very special teeth is able to rip out, even with very large food portions, unproblematic bite-sized pieces. If the animal is full, it rests on its favourite place, but even this phase is interrupted in irregular fashion and swims in one or two rounds through the tank, before it rests itself back there again . As well as we never see our specimen digging, so plants will not be damaged, however they should be firmly fixed in the bottom, because otherwise with the occasionally hectic movements of the catfish, they will be uprooted.

 

 

C. macropterus can be associated with congeners. For this purpose one lets them grow up together, best with two or three young animals.

They are predatory catfish with fast growth, but although somewhat dependent on the aquarium size too, 10 to 15 centimetres long specimens grow more than the double of there own length in the first year of there keeping.

About five years old, specimen of 45 cm in length and a weight of over 1 kg, resting on its favourite place.

 

 

Among one another this species even looks for body contact: Two young animals of same size, which we socialised with one another, often would lie together, until one starts abruptly and after a short excursion in the tank associates itself again with the other one. Every now and then they do some rounds together and then push themselves mutually together. Possibly the social behaviour shown here is already conditioned as sex specific. There are still no consolidated findings to possibly present any sexual differences, probably however with adult animals the males are slimmer. Altogether C. macropterus is somewhat more active when socialising with congeners than during single keeping.

Young specimen of 13 cm in length, whose colouring is brighter than with older animals.
Disputes among themselves are to be observed rather rarely. They bite obviously only if the size differences are noticeable or one tries to bring together an older specimen after longer single keeping with a possibly younger animal, then the smaller species can be seriously hurt and regarded even as food. If one adds other fish species which fit into the predatory pattern of the catfish, and this counts for example all livebearers from the Poeciliidae family, in addition Cyprinidae like the gold fish (Carassius auratus auratus), then C. macropterus immediately begins the pursuit. It skillfully understands to press its victim under usage of the forward spread and thereby making a larger radius of action possible with its upper barbels for a long time until biting is possible.

 

 

If the catfish cannot devour the prey fish at one time it will, and also here the parallels to the sea predator are unmistakable, be made disabled by a bite in the tail fin or a separation of the complete tail. Attracted by the smell and the death fight of the prey the possible species companions also take part, then the rest of the prey is fed by all in a true devour orgy. The first attack is already done so fast that an intervention of the keeper usually comes too late.

The upper barbles of Calophysus macropterus are very long and reach back to the end of the caudal fin.

 

 

Conclusion:
C. macropterus is a really impressive and quite active species. For many catfish lovers it is manageable and at a just acceptable final length, and in addition contrary to some other predatory species, at all ages a complete beauty, making it an absolute recommendation.

When reasonable planning even socialization is possible. Under aquaristic aspects this interesting catfish to this day is undervalued and could be more frequently seen in big home aquariums to convince astonished visitors of its attractiveness.

An eye catcher in the big aquarium. With this specimen the bluish colouring is particularly strongly pronounced.

This article was published in April 2008 in the German publication: "Die Aquarien und Terrarienzeitschrift" (Datz) 61 (4): 16-18.

Our thanks apply here for the Datz editorship and their editor-in-chief, Rainer Stawikowski, who gave us kind permission to publish this article on ScotCat.

© Copyright text and photos, Datz, published here with permission.