Author Archives: Frank Schäfer

The yellow Congo tetra (Alestopetersius caudalis) is a popular and frequently offered ornamental fish. The species originates from the Congo, where it is at home in the lower reaches of the African river. Wild-caught fish are very rare in the trade. The species was first imported around 1950 and was soon bred. The animals in the trade today are almost without exception captive-bred, mostly from Indonesia, but other professional breeders in Europe and Asia also have the species in their range. 

On the occasion of the presentation of a small video (https://www.youtube.com/watch?v=7uXLpgRDoME), the question was raised via the comments function as to whether the animals shown (captive-bred from Indonesia) are not Alestopetersius tumbensis rather than A. caudalis. In fact, the two species are extremely similar and they also occur together – at least in places. From a scientific point of view, the most important difference between the two is the shape of the teeth: five-pointed in caudalis, many-pointed (8-9 points) in tumbensis. The different tooth shape was considered so important that a separate genus Duboisialestes was even established for tumbensis (plus bifasciatus). In addition, preserved specimens can be distinguished by their black markings. In A. caudalis, a broad dark longitudinal band extends from the shoulder patch to the caudal fin, whereas in A. tumbensis the longitudinal band is much narrower and there is a clear gap between the shoulder patch and the longitudinal band. Unfortunately, you can’t see this at all in live specimens, or can only see a hint of it.

The question came as a surprise to us, because although the species A. tumbensis (the genus Duboisialestes was declared a synonym of Alestopetersius by Munene & Stiassny in 2012) was described in 1951 on the basis of specimens imported into the Netherlands for the ornamental fish trade, it has not been mentioned in the hobby since then as far as we know. We do not kill animals for identification purposes, but we were able to recognize the shape of the teeth from a macro photograph of the mouth of one of our fish: clearly five-pointed, i.e. A. caudalis.

The exact species identification of African small tetras is and remains a complex matter. Not only aquarists have difficulties with this, but also professional ichthyologists. The markings given in the scientific papers (especially black bands, stripes etc.) are, as already mentioned, often only vaguely recognizable or not recognizable at all in living animals. The lesson for us from this story is that we will look twice as closely the next time we import wild-caught yellow Congo tetras. Perhaps we will discover A. tumbensis among them and then be able to provide a live photo of the species (as far as we know, none exists so far). Who knows, maybe you can also see differences between the two species in live animals …

By the way: general information on Alestopetersius caudalis can be found here: https://www.aquariumglaser.de/en/fisharchive/alestopetersius-caudalis-2/

For our customers: the animals shown in this post, captive bred from Indonesia, have code 138004 (xlg) on our stocklist. Please note that we only supply the wholesale trade.

Literature:

Boulenger, G. A. (1899): Matériaux pour la faune du Congo. Zoologie.–Série I. Poissons nouveaux du Congo. Quatrième Partie. Polyptères, Clupes, Mormyres, Characins. Annales du Musee du Congo (Ser. Zoologie) v. 1 (fasc. 4): 59-96, Pls. 30-39.

Géry, J. (1995): Description of new or poorly known Alestinae (Teleostei: Characiformes: Alestidae) from Africa, with a note on the generic concept in the Alestinae. aqua, Journal of Ichthyology and Aquatic Biology v. 1 (no. 4): 37-64.

Hoedeman, J. J. (1951): Studies on African characid fishes I. The tribe Alestidi. Beaufortia v. 1 (no. 3): 1-8.

Mbimbi Mayi Munene, J. J. & M. L. J. Stiassny (2012): A new Alestopetersius (Characiformes: Alestidae) from the Kwilu River (Kasai basin) of central Africa; with a phylogeny for the genus and synonymy of Duboisialestes. Zootaxa No. 3166: 59-68.

Poll, M. (1967): Révision des Characidae nains Africans. Annales, Musée Royal de l’Afrique Centrale, Tervuren, Série in 8o, Sciences Zoologiques No. 162: 1-158

Text & photos: Frank Schäfer

The Parodontidae are a relatively small group of bottom-dwelling tetras. The family consists of three genera with a total of approx. 32 species. The genera are distinguished from each other by two characteristics: firstly, the number of unbranched rays in the pectoral fin: one each in Parodon and Apareiodon and two in Saccodon; and secondly, the lack of teeth in the lower jaw in Apareiodon and Saccodon, whereas Parodon has teeth there. Unfortunately, the dentition features are not recognizable in living animals, which is why species identification and even genus assignment is often only very vague, as all species have a fairly generalized appearance. The differentiation of species in scientific descriptions is also mainly based on the shape of the teeth. In the hobby, however, the family Parodontidae is only occasionally represented by a single species, namely Apareiodon affinis from Paraguay (see https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/apareiodon-affinis-2/), which is why they are rarely encountered.

We have now been able to import a member of the Parodontidae from Peru. As all the specimens arrived alive, it was/is not possible to identify them precisely. However, only three species of Parodontidae are known from Peru so far: Parodon buckleyi, P. pongoensis and Saccodon wagneri. So we started by looking at the descriptions of these three species, which fortunately are all illustrated. This enabled us to quickly rule out Saccodon wagneri, which was described in 1863, as in this species the dorsal fin is so far forward that its end is still before the base of the pelvic fins. In our fish, the dorsal fin sits roughly above the pelvic fins. This leaves Parodon buckleyi, described in 1887, and P. pongoensis, described in 1942. Both look very similar; however, P. pongoensis is known in scientific collections with specimens from the vicinity of Pucallpa (drainage of the Rio Ucayali), while P. buckleyi is reported much further north. As the Pucallpa region is an important area for ornamental fish collectors, it is quite likely that our specimens come from there and belong to the species Parodon pongoensis. However, we do not have any final certainty about this, which is why we refer to the species on our stock list as Parodon sp. cf. pongoensis (the “sp. cf.” means “not exactly determined, but very similar to”).

Apart from the occurrence in Peru, which is also the type locality of P. pongoensis (forest brook, foothills at Pongo de Manseriche, Marañón River drainage, Peru), this species is widespread and also occurs in the drainage of the Orinoco in Colombia, adjacent to Peru in Ecuador and further south in Brazil (state of Goiás, Formosa, river Água Quente, tributary of the Paranã, catchment area of the Tocantins). The maximum length is probably around 12 cm. In larger animals, the lower caudal fin lobe turns more and more black; this is not yet visible in our juveniles, which are currently 3-4 cm long.

We have not noticed any special features in terms of care so far. The lively animals like to swim in groups with their own kind. Other fish are hardly noticed. The water temperature can be between 22 and 26°C. The water values are unimportant as long as the water is clean. They feed on aufwuchs and can be used as “algae eaters”. However, they will also eat pretty much any common ornamental fish food that fits in their mouths. P. pongoensis is therefore a diurnal algae eater for South American aquaria, a stylish alternative to the always somewhat secretive suckermouth catfish.

For our customers: the animals have code 275882 on our stocklist. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

The regrouping of large fish families continues. After the barbs, armored catfish and cichlids, it’s now the turn of the characins. A major revision was published in September 2024, prompting us to retrain once again. Not all tetra species have been included yet, so it will certainly take a few years before the new name combinations are generally used. We are also being conservative and cautious for the time being and are waiting to see what the future brings. 

Aquarists can easily follow the reintroduction of the genus name Megalamphodus for the phantom and rosy tetras in the broadest sense. In English they are all referred to as “rosy tetras”, based on the most common species in the hobby, Megalamphodus rosaceus (formerly often referred to as Hyphessobrycon ornatus, see https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-rosaceus-ornatus-2/). Within the rosy tetras, three species are well defined, namely the bleeding hearts. There are three of them: M. erythrostigmus (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-erythrostigma-2/), M. pyrrhonotus (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-pyrrhonotus-2/) and M. socolofi (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-socolofi-var-green-2/. All have a bright red shoulder spot, which has earned them the interantional name bleeding hearts.

In spring we often receive very large and fully-grown Megalamphodus erythrostigmus ( = Hyphessobrycon erythrostigma) from Peru, very magnificent fish, as is the case now. We would like to take this opportunity to point out the name changes.

For our customers: the animals have code 260107 (sh, i.e. show size) on our stocklist. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

The lemon tetra, Hyphessobrycon pulchripinnis, is one of the most popular aquarium fish of all and can be found in the standard range of pet shops all over the world. As with so many everyday species, little thought is given to them, but the lemon tetra holds many secrets!

Its native habitat was unknown until 1980, although the species was described as early as 1937. The first description was based on aquarium fish imports whose origin was unknown and only vaguely stated as “probably Amazonas”. Although breeding the fish is not easy (randomly matched pairs often do not spawn, the females have to be brought to spawn at regular intervals so that the spawn remains fertile, etc.), wild catches were hardly ever made and it was not until 1980 that Gery discovered that the home of the lemon tetra is in the lower Amazon basin, more precisely in the middle and lower Tapajós between Itaituba and Jacare Acanga, as well as in streams that flow into the Rio Curua do Sol. Other authors also mention the Xingu and the Tocantins.

We have recently received wild catches of H. pulchripinnis from the Rio Cuiaba in the state of Mato Grosso (Brazil). This is an extremely rare event and gave us food for thought. As you can see from the picture of our supplier, freshly caught animals are crystal red. But in the aquarium, the animals usually discolor. This phenomenon is known from many fish species. The cause is most probably our clean aquarium water. In nature, the water is almost always cloudy due to clay or other suspended particles. The coloration of a fish cannot be controlled arbitrarily. This is done by hormones whose production is triggered by stimuli perceived by the eye (light, shade, water turbidity, color of the substrate, etc.). Although this explains very well why most fish in bright, sparsely furnished aquariums with little structure are very pale in color, it does not explain why they sometimes show bright colors after a certain period of time.

A group of “Muzel Red Cherry” tetras are swimming in one of our tanks in the show aquarium at Aquarium Glaser. They are imports from Brazil, but we assume that they were bred there. The Muzel are predominantly bright red-colored animals, but there are also some with a yellow body color. These yellow animals look very similar to lemon tetras. In the yellow Muzel tetras, the shoulder spot (= humeral spot) is also strongly pronounced, which is only very faintly visible in red Muzel tetras. All fins of both Muzel colors are bright red. This clearly distinguishes them from “true” lemon tetras, which at best have faintly orange dorsal and anal fins. The caudal fin of “true” lemon tetras is always transparent and colorless. “Bolivia Orange” lemon tetras also have this characteristic (see https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessonbrycon-cf-pulchripinnis-bolivia-orange/). 

Obviously there is a whole circle of forms around H. pulchripinnis, which includes the following species/forms: 1. the “classic” H. pulchripinnis, which has been at home in aquaria since 1937 (colorless caudal fin, usually also dorsal and anal fins, anal fin with yellow and black line on the leading edge, dorsal fin also with black on the leading edge); 2. the pulchripinnis “Tapajós”, as illustrated in the Aquarium Atlas Volume 1 (cuvette photo on site), which lacks the black line at the beginning of the anal and dorsal fin; to our knowledge, this species is not represented in the hobby or is not distinguished from the “normal” lemon tetra; 3. the “Bolivia Orange”, which has existed in the hobby since around 1980 (colorless caudal fin, dorsal and anal fins bright red, black line at the front edge of the anal fin missing); 3. the “Muzel Cherry Red”, in which all fins and the body are bright red, black line on the front edge of the anal fin is missing, in the hobby since about 2021; 4. the “Muzel Yellow”, which looks like the “Muzel Cherry Red”, but with a yellow-orange body. The mystery surrounding the sometimes crystal red “normal” lemon tetras remains unexplained, of which our supplier wrote to us: “In fact I see most of the tetras from Cuiaba like this (note: red is meant), I have already received some to send to China and after a few weeks most of them lose their color, or some get a better color…. it’s a shot in the dark…”

Keeping all lemon tetras is very easy and even beginners can manage it. The up to 4.5 cm in length animals are kept in groups in well-structured aquaria, where each fish soon occupies a tiny territory. They will eat any common fish food and the temperature can be between 22 and 28°C. The water should (but does not have to) be soft and slightly acidic, then the colors are at their best.

For our customers: the “normal” captive-bred lemon tetra has code 261603, the wild-caught tetra from the Mato Grosso 261642 on our stock list. Please note that we only supply the wholesale trade.

Text: Frank Schäfer, photos: H.-J. Mayland, E. Schraml, F. Schäfer

The lemon tetra, Hyphessobrycon pulchripinnis, is one of the most popular aquarium fish of all and can be found in the standard range of pet shops. As with so many everyday species, little thought is given to them, but the lemon tetra holds many secrets!

The ancestors of the animals that we can occasionally offer as beautiful captive-bred specimens are said to originate from Bolivia. They differ from the well-known lemon tetra (from Brazil) by their intense orange color and the absence of the otherwise typical black fin fringe in the anal fin. According to our breeder, the fish also differ in their spawning behavior. This orange lemon tetra is therefore presumably a new, undescribed species.

They are very easy to keep and can even be kept by beginners. The up to 4.5 cm long animals should be kept in groups in well-structured aquaria, where each fish soon occupies a tiny territory. They will eat any common fish food and the temperature can be between 22 and 28°C. The water should (but does not have to) be soft and slightly acidic, then the colors are at their best.

For our customers: the new animals, which we call “Orange Bolivia”, have code 261632, the classic lemon tetra 261603. Please note that we only supply the wholesale trade.

Text Frank Schäfer, Photos: Frank Schäfer and H. J. Mayland/Aqualog-Archives

Of course, this fish is anything but a novelty and has been imported in relatively large numbers for many years. But isn’t it beautiful? This small animal is an ideal companion for the cardinal tetra (Paracheirodon axelrodi), with which it also occurs in the wild. Poecilocharax weitzmani grows to 3-4 cm and is relatively widespread in the upper Amazon and upper Orinoco. It is found in Colombia, Venezuela, Brazil and Peru. Despite its large mouth, it is a peaceful fish. 

However, P. weitzmani is a truly special characin, as – in contrast to most other characin relatives – it is a cave breeder with brood care. In the aquarium, the males occupy hollow pieces of bamboo as breeding grounds and guard the spawn there until the young hatch. However, breeding is not easy, because in order for the spawn to develop well, you need water values similar to those in nature: hardness practically undetectable and pH around 4.5-5. You need some experience to keep such water stable over a longer period of time. It is therefore not advisable to aim for such water values for normal keeping. Just as with the cardinal tetra, the adaptability to water values as they come out of the tap in Central Europe is very good. Even in such water, the small fish reach an age that is 5-10 times longer than in the wild.

We can currently offer P. weitzmani from Colombia and Brazil. Basically, we can’t see any visual differences between the two local forms, but the Brazilian specimens are currently much larger, almost fully grown. And among them are a few (1-2 animals per 500 specimens) male individuals with a brilliant red coloration that we have not (consciously) seen before. So far, P. weitzmani has only been bred by specialists interested in behavioral studies due to its abundance and the resulting low price; breeding is not economically worthwhile. It is possible that this will change now that this magnificent variety has become known.

There are observations from aquarists that describe P. weitzmani as shy. This does not correspond with our observations. The animals photographed, for example, were imported only a few days ago and already present themselves as if they had been born there in the very sparsely furnished photo tank with a few pieces of wood and leaves. With regard to all care factors (food, temperature, lighting, furnishings), please refer to the extensive literature on cardinal tetra. P. weitzmani does not have any significantly different requirements with the exception of the aforementioned spawning caves.

For our customers: the animals have code 281004 (md-lg) and 281005 (lg-xlg) on our stocklist. Please note that we only supply the wholesale trade.

Text & Photos: Frank Schäfer

The genus Tetragonopterus used to be the catch-all for all smaller tetra species, which are now found in the genera Hemigrammus, Hyphessobrycon or Moenkhausia, for example. The English term “tetra” for all tetras, an abbreviation of Tetragonopterus, has survived. Nowadays there are only 14 species of Tetragonopterus, of which only T. argenteus can be considered an aquarium fish (see: https://www.aquariumglaser.de/en/fisharchive/tetragonopterus-argenteus-2/). Incidentally, 9 of the current 14 species were only scientifically described after 2010; it is therefore obvious that they look very similar, otherwise they would certainly have been recognized earlier; the majority of them were previously assigned to T. chalceus.

We have now been able to import a Tetragonopterus species from Brazil under the name T. chalceus, and in order to identify it, we began a major literature search. Initially, we provisionally classified it as T. chalceus, as this is how it would have been designated before 2010. We cannot take into account some important characteristics for the systematics of tetras, such as the shape and number of teeth or the gill rakers, because they cannot be recognized on the living animal and we do not kill animals for identification purposes. But color characteristics are also important for identification. Our Tetragonopterus, for example, has two elongated, vertical shoulder spots ( = humeral spots) and a circular tail root spot. 

According to the latest identification key (Silva et al., 2016), T. argenteus, T. carvalhoi, T. daguae, T. rarus and T. georgiae can be ruled out from the outset (scale and pattern characteristics). T. anostomus and T. kuluene (both only one humeral spot) can also be ruled out. This leaves T. araguaiensis, T. denticulatus, T. juruena, T. ommatus, T. manaos, T. franciscoensis and T. chalceus. At this point T. chalceus was ruled out, because in this species there is only one scale width between the two humeral spots, whereas in our imports there are three. T. juruena and T. denticulatus differ, among other things, by 6 rows of scales between the lateral line and the dorsal fin base (T. juruena) and 7 rows (T. denticulatus); T. juruena was thus eliminated. Although T. franciscoensis is very similar to our specimens, it is only found in north-eastern Brazil; however, our fish are certainly not from there. According to the exporter, they originate from the Rio Tocantins; T. araguaiensis and T. denticulatus occur there (both described from the Rio Araguaia, which is a tributary of the Rio Tocantins). Unfortunately, the species diagnoses are limited to the number of gill rakes. But a careful comparison of the illustrations of both species makes it more likely that our imports are T. denticulatus. T. ommatus – just for the sake of completeness – is so far only known from the middle Rio Tapajós and the last species described (2018), T. manaos, comes from the Rio Negro.

We have described the identification process in such detail because fish such as Tetragonopterus denticulatus are certainly only of interest to specialists and collectors of rarities, who usually attach great importance to correct identification. The pictures we show here are probably the first live photos of the species. The large eye is striking, indicating a crepuscular lifestyle. The animal does not appreciate bright light at all. The maximum length of T. denticulatus known to date is around 7 cm (without caudal fin). Accordingly, our animals (4-6 cm) are probably sexually mature. They are very peaceful, lively and somewhat skittish. The animals actively seek the company of conspecifics, so they are to be regarded as schooling fish. So far, we have not noticed any special care requirements and the fish can be characterized as extremely easy to care for.

For our customers: the animals have code 296353 on our stocklist. Please note that we only supply the wholesale trade.

Literature

Silva, G. S. C., B. F. Melo, C. Oliveira & R. C. Benine (2016): Revision of the South American genus Tetragonopterus Cuvier, 1816 (Teleostei: Characidae) with description of four new species. Zootaxa 4200 (no. 1): 1-46

Urbanski, B. Q., B. F. Melo, G. S. C. Silva & R. C. Benine (2018): A new species of Tetragonopterus (Characiformes: Characidae) from Central Amazon lowlands, Brazil. Neotropical Ichthyology v. 16 (no. 2) (e3170158): [1-7]

Text & photos: Frank Schäfer

The correct naming of piranha species is one of the most difficult chapters in fish systematics. Even the scientists specializing in this group of fish are by no means in agreement. And so we often have little choice but to identify a newly imported piranha according to the few external characteristics that are generally recognized, such as the black bands in the caudal and anal fins, the presence of a shoulder spot, etc.

Serrasalmus spilopleura is a rather round-headed piranha by Serrasalmus standards, which according to literature is distributed throughout the Amazon and Orinoco basins. Terra typica is Rio Guaporé, Bobota, Mato Grosso, Brazil. There is a possibility of confusion with S. maculatus, which was also synonymous with S. spilopleura for many years. S. maculatus from Paraguay has exactly the same caudal fin coloration as S. spilopleura from the Rio Tocantins, but S. maculatus always lacks the red gill cover area. It is often difficult to recognize atypically coloured specimens in individual cases. 

Serrasalmus spilopleura is a beautiful piranha, certainly one of the most attractive species of the whole group. The exact origin of the animals currently imported by us is the Rio Guama (drainage of the Rio Tocantins). Serrasalmus species are considered to be specialized fin eaters. For this reason, individual keeping is generally recommended, as if you keep several specimens together, you will hardly ever see undamaged animals, even with heavy feeding. In the aquarium, these piranhas will eat all the usual coarse frozen foods, as well as earthworms, food fish (frozen smelts are very suitable as a basic food) etc. They can be expected to reach a length of 20-25 cm. The water values in terms of pH and hardness are insignificant, but good water hygiene should be ensured. The water temperature should be in the range of 24-28°C

For our customers: the fish have code 292823 (6-8 cm) and 292824 (8-10 cm) on our stock list. Please note that we only supply the wholesale trade.

Lexicon: Serrasalmus: from Latin, roughly means “salmon with a saw”. Refers to the saw-like scales of the breast keel. spilopleura: ancient Greek, means “with spotted sides”. maculatus: Latin for spotted.

Suggestion of a popular name: glowing coal piranha

Text & Photos: Frank Schäfer

The elegant predatory tetras of the genus Boulengerella are divided into 5 species: B. cuvieri, B. lateristriga, B. lucius, B. maculata and B. xyrekes. They are widely distributed in the large river systems of the Amazon and Orinoco and the Guyanas. Distinguishing the species is not easy, especially with small juveniles. Juveniles of B. cuvieri differ from their relatives in that the lower caudal fin lobe is considerably larger than the upper one. Very small animals (4-5 cm) still have the ancient extension of the spine as the upper edge of the caudal fin. This quickly disappears; from a total length of approx. 6 cm you can recognize the species-typical caudal fin structure with a smaller upper and larger lower caudal fin lobe. B. cuvieri retain their dark cloudy juvenile coloration up to a total length of approx. 10 cm. Then the species-typical adult coloration appears with a light back, a chocolate-colored longitudinal band in the middle of the body and a silvery belly. There is then a small spot on the root of the tail. With increasing age, the caudal fin turns a strong orange-red color. Other typical characteristics of B. cuvieri are the strangely shaped anal fin, the rearmost rays of which are so long that they protrude beyond the base of the caudal fin, and the dorsal fin, which is set far forward.

All Boulengerella species can be easily distinguished from about 10 cm in length. B. lateristriga is the only species with a striking black and white striped caudal fin. B. lucius and B. maculata are almost identical in color, both are dotted on the body and have an irregular spot/striping in the caudal fin, but in B. lucius the dorsal fin sits much further towards the head on the back, so that an imaginary vertical line from the end of the dorsal fin towards the ventral edge comes out well before the base of the anal fin (the same applies to B. cuvieri), whereas in B. maculata it is in the middle of the anal fin. At 10 cm in length, B. xyrekes looks a little like a small juvenile of B. cuvieri, but in B. xyrekes both caudal fin lobes are about the same size and the rearmost anal fin rays end well before the base of the caudal fin.

Boulengerella cuvieri is the largest species of the genus. It can grow to a record size of almost 1 m long and weigh 6 kg. The species has a huge distribution area in South America and is found practically everywhere in the Amazon and Orinoco basins and in the Guyana countries. Imports mostly come from Peru, Venezuela and Colombia. The predatory tetra inhabits various types of water in its native area, but is most frequently found in fast-flowing waters, where it lurks for prey behind obstacles such as rocks and tree trunks. As a rule, it stays below the water surface and is an excellent jumper (cover the tank well). When keeping them in an aquarium, care should be taken to ensure that they are kept as stress-free as possible, as otherwise uncontrolled flight reactions may occur. The animals easily bump into the walls of their tank and can injure their sensitive mouths. As fish eaters, they should be fed with live or frozen fish. It goes without saying that they should only be kept with fish of the same size, as small inhabitants are regarded as food. The animals are peaceful with each other and like to be in the company of conspecifics.

For our customers: the animals have code 210403 (approx. 10 cm) on our stock list. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

Hyphessobrycon columbianus was described by Zarske & Géry in 2001. According to Weitzman, the fish belongs to the “Rosy Tetra group” (in the broadest sense “ornamental tetra relatives”). The first specimens arrived in Germany in 1995, caught in a tributary of the Rio Acanti, Colombia. All specimens currently on the market are said to be descended from the first few imports.

Shortly after its discovery, this fish was reproduced en masse and offered in the trade (until its scientific description, mostly under the names Astyanax spec. or Hyphessobrycon ecuadoriensis), which is why the initially considerable price quickly fell to a “lower tetra level”. Hyphessobrycon columbianus is an enrichment for the aquarium hobby due to its splendid colors, peacefulness and ease of breeding, although it does fade somewhat if not kept under optimal conditions. The water should be somewhat cooler (<25 °C) and harder, the pH neutral to slightly alkaline. The animals also appear to be occasionally susceptible to (bacterial?) infections.

For our customers: the animals have code 259952 on our stocklist. Please note that we only supply the wholesale trade.

Photos: Frank Schäfer, Text: Peter & Martin Hoffmann

The predatory tetras of the genus Erythrinus should be easy to identify, because from a scientific point of view only two species are accepted: E. erythrinus, which inhabits virtually the entire tropics and parts of the subtropics of South and Central America, and E. kessleri, an endemic (i.e., occurs only there) from the state of Bahia in Brazil. However, Erythrinus imported from different regions look very different. We call the most frequently imported, very colorful form from Peru Erythrinus erythrinus (without this being scientifically confirmed), see https://www.aquariumglaser.de/fischarchiv/erythrinus-erythrinus-peru/ there also further general notes.

We have received Erythrinus from Colombia and Venezuela that are completely different in color from the Peruvians. These fish also look very different from each other; we suspect that males and females are behind the different coloration. As these Erythrinus come from the Orinoco catchment, we have labeled them accordingly on our stock list.

We assume that these fish, like all Erythrinus, grow to 20-25 cm in length. They are typical predatory fish. Also the keeper should take care of his fingers, because the jumping animals like to bite heartily and that bleeds properly!

For our customers: the animals have code 253385 on our stocklist. Please note that we only supply wholesale. Only available in very small quantities!

Text & photos: Frank Schäfer

In 2010, we were able to import a new tetra from Brazil via Belem for the first time, which could not be clearly assigned to any scientifically described species. It was provisionally named Hyphessobrycon cf. stegemanni and Phoenix tetra. Today we know that the species originates from the Rio Araguaia. The maximum length is 3-4 cm. Males differ from females in that their fins are longer and the caudal fin is red in males and transparent in females.

Just one year later – in 2011 – the Phoenix tetra was scientifically described by Zarske as the new species Hemigrammus filamentosus. The scientific description is freely available here: https://vertebrate-zoology.arphahub.com/issue/4367/

In the meantime, the species has become firmly established as an aquarium fish and is mainly offered in the form of captive-bred fish. From time to time, however, there are also wild catches. Golden Hemigrammus filamentosus are then also offered, which are very attractive. Golden forms are only available as wild-caught specimens, as the triggers for the golden coloration are transmitted via bird droppings. This does not occur in human care.

In terms of care, the species can be classified as undemanding. They are peaceful animals that are not dangerous to conspecifics, other fish or plants. From around 28°C the males start their wonderful courtship games and harmless chases, during which not even the long fin filaments are affected.

For our customers: the fish have code 256433 (captive bred), 256423 (wild, normal color) and 256424 (wild, gold form) on our stocklist. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

The piranha species Serrasalmus gibbus comes from the catchment of the Rio Tocantins, it was described from the Rio Araguaia. The animals that we currently have in stock were delivered with the location Guama. The Rio Guama is a 160 km long tributary of the Tocantins in the state of Pará, Brazil. 

The species is quite elongated and, like S. rhombeus, which it looks very similar to, has a black caudal fin margin. A humeral spot is missing in younger specimens, but becomes more prominent with increasing age and is very large and prominent in adult specimens (from about 15 cm in length). The main differences to S. rhombeus are the rather small and round humeral spot in S. rhombeus (large and highly oval in S. gibbus) and the crystal red eye of S. rhombeus (dirty dark red in S. gibbus). The reduced dot pattern of adult animals is characteristic of the species, the back appears greenish (although this also depends on the incidence of light). The body shape of S. gibbus is also characteristic of the species. In adults, the greatest height of the body is at the end of the occiput, after which the dorsal line drops continuously. The species name “gibbus” (= humpbacked) is aptly chosen. 

In the trade, S. gibbus is often referred to as the “Peruvian piranha”, which is very misleading, as the species does not occur in Peru at all, but is endemic to the Tocantins catchment. At 20-25 cm in length, S. gibbus is fully grown. As is usual with Serrasalmus, it is a fin-biter that usually has to be kept individually. You should not be misled by the fact that we like to have two animals in the photo tank for dramaturgical reasons. This only ever happens for a very short time and under constant supervision.

For our customers: this very rarely offered piranha has code 292003 (7-9 cm) on our stock list. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

The title of this post is perhaps a little misleading; it is intended to indicate that the species recently scientifically described as Myloplus sauron has been known in the hobby as Myleus schomburgkii for around 100 years. However, M. schomburgkii still exists. Back in 2004, the genus Myloplus was separated from Myleus and M. schomburgkii was placed under Myloplus. Until June 2024, all Myloplus with a black vertical band on the flank were classified as M. schomburgkii.

A recent revision of the group revealed that there are not one, but three species with a vertical black bar on the body flank. Aquarists have long been familiar with “broad-banded” and animals with narrow bands. The latter are the most common in the hobby, not least because they are bred in SE Asia for the ornamental fish market. The species with a narrow body band has now been renamed and described as Myloplus sauron. It originally comes from the Rio Xingu in Brazil.

Broad-banded Myloplus are widespread in Brazil and Venezuela in the middle and lower reaches of the large river systems of the Amazon and Orinoco. This is the “true” Myloplus schomburgkii. However, there is a second broad-banded Myloplus that occurs in the western Amazon basin of Peru and Brazil, i.e. the upper areas. This new species is now called M. aylan. It is not easy to distinguish between M. schomburgkii and M. aylan, so anyone interested should refer to the free and freely accessible original scientific description: https://www.scielo.br/j/ni/a/fFG9HTqKTjCs4Z4W3MxwSLJ/?format=pdf&lang=en

In any case, the “true” M. schomburgkii is the most colorful of the three species. M. aylan is more discreetly colored. While in M. schomburgkii the red coloration of the male can extend over the entire body, in male M. aylan it is essentially limited to the throat area. M. sauron shows the least color. The areas around the gill cover and front breast are only yellow-orange, sometimes reddish (especially in young specimens). Young sexually mature wild-caught males developed black-colored zones in the belly area at a size of 12-15 cm.

By the way: the three show such serious differences in the DNA structure that it is quite likely that they will end up in different genera in the future. And there are several color forms of M. schomburgkii (the “real” one) with clearly different colors. It is quite likely that some of these will be separated as separate species in the future.

You can find photos of M. aylan here: https://www.aquariumglaser.de/en/fisharchive/myloplus-schomburgkii-big-black-stripe-2/

You can find photos of M. schomburgkii here: https://www.aquariumglaser.de/en/fisharchive/myleus_schomburgkii_en/

We can offer the “new” Myloplus sauron very regularly, the other species are only offered very occasionally. All Myloplus can grow quite large, approx. 30-40 cm. They are magnificent animals, but only suitable for owners of really large aquaria. There they are very long-lived. One disadvantage of these fish is that they regard pretty much any aquatic plant as additional food.

For our customers: M. sauron has code 270501 (3-4 cm) and 270505 (8-11 cm) on our stocklist. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer

The most common “gold tetra” in the trade comes from Colombia and is generally traded under a false name. It can be found in the trade up and down the country for little money under the name Hyphessobrycon eos (sometimes also as Hemigrammus eos). The species Hyphessobrycon eos actually exists, but it is not kept in the aquarium. H. eos Durbin, 1909, originates from Guyana and there are currently no significant exports from there; we don’t even have any photos of H. eos in our huge picture archive. Too bad, because Jonathan Armbruster has published a picture of the species in Flickr, which shows a very pretty fish (https://www.flickr.com/photos/jonarmbruster/15464514263/).

Be that as it may, the gold tetra imported from Colombia (and sometimes also from Venezuela and Peru) is Hyphessobrycon saizi, as Axel Zarske found out. The golden sheen is caused by the increased release of the pigment guanine in the skin, which is caused by infection with worm larvae. The fish are only intermediate hosts for the worms. The fish become infected by eating infectious bird droppings. If this happens, the worm larvae migrate into the muscles of the fish, where they encapsulate. Basically, even if it sounds disgusting, this is harmless and the infected fish live – at least in the aquarium – just as long as their non-infected conspecifics. However, their striking golden coloration attracts the increased attention of fish-eating birds – the final hosts of the worms. If a golden tetra is eaten by a bird, the encapsulated worm larvae hatch in its intestine and develop into a sexually mature worm. These produce large quantities of eggs, which are excreted in the bird’s feces – and the game starts all over again.

This explains why golden tetras are always wild-caught in the trade. Offspring of golden tetras are invariably normal-colored and there is no interest in wild-colored Hyphessobrycon saizi in the hobby; we only show also pictures of the non-gold-colored form here for informal reasons. With a maximum size of around 2.5- 3 cm, Hyphessobrycon saizi fits perfectly into any well-maintained community aquarium. It is a typical companion fish of the Colombian red neon in the wild and is a perfect contrast fish to this species. Younger specimens of the Colombian golden tetra in particular have more or less intense red tail fins, which looks very pretty. Unfortunately, this fades somewhat with age. The golden sheen, on the other hand, remains for life.

Literature:

Eigenmann, C. H. (1912): The freshwater fishes of British Guiana, including a study of the ecological grouping of species, and the relation of the fauna of the plateau to that of the lowlands. Memoirs of the Carnegie Museum v. 5 (no. 1): i-xxii + 1-578, Pls. 1-103.

Zarske, A. (2013): Hyphessobrycon saizi Géry, 1964 – der Kleine Silbersamler, seit Jahren inkognito. Aquaristik Fachmagazin 229 (Februar/März 2013): 42-46

Text & photos: Frank Schäfer