Original description as Chromis rivulata:
- Günther, Albert C. L. G. 1860. "Second list of cold-blooded vertebrata collected by Mr. Fraser in the Andes of western Ecuador". Proceedings of the General Meetings for Scientific Business of the Zoological Society of London. 1859 (pt 27), pp:402-420 (crc00005)
- Acara aequinoctialis, with type locality at West Ecuador. Determiner: Kullander, 2003
- Aequidens azurifer, with type locality at Affluent of the Río Chimbo near Bucay, Guayas Province, Ecuador. Determiner: Kullander, 2003
- Chromis rivulata, Günther, 1860, original combination.
- Acara pulchra, Günther, 1862, misidentification (part. (specimens b-d)).
- Astronotus (Aequidens) rivulata, Eigenmann et al, 1894, new combination.
- Acara rivulata, Boulenger, 1899, new combination (part. (all except the first of the 'types')).
- Aequidens rivulatus, Eigenmann et al, 1903, new combination.
- Acara aequinoctialis, Regan, 1905, junior synonym.
- Aequidens rivulatus, Starks, 1906, new combination (part.).
- Aequidens azurifer, Fowler, 1911, junior synonym.
- 'Aequidens' rivulatus, Stawikowski et al, 1998, provisional name.
- Andinoacara rivulatus, Musilová et al, 2009, new combination.
- Habitat: Rivers: main channels, Rivers: pools, Secondary rheophilus
- Feeding: Feeding unknown
- Morphology: Large cichlids
- Aquarium: Intermediate aquarists
- Breeding: Monogamous parental, Substrate brooders
Etymology: rivulatus = provided with small brooks (Latin); referring to the blue streaks on the pre-orbital and cheeks.
Types: The lectotype, BMNH 1860.6.18:13, and three paralectotypes, BMNH 1860.6.18: 14-16 are deposited in the Natural History Museum, London (formerly British Museum of Natural History). Two further paralectotypes are stored in the Museum für Naturkunde, Berlin (formerly Zoologisches Museum) under the registration number ZMB 2809 (Paepke & Schindler, in prep.). The lectotype was designated by Wijkmark & al. (2012). A previous lectotype designation by Regan (1905) is invalid, see comments.
Diagnosis: Andinoacara rivulatus is most closely related to A. stalsbergi and A. blombergi. These three species differ from all other Andinoacara in the overall shape of adults (dorsal head profile straight, nape curved, tendency to develop a nuchal hump in males vs. head profile more evenly convex; dorsal fin base almost straight vs. gently curved; greatest body depth below anterior vs. middle dorsal fin spines), in predorsal squamation (8-12 [usually 9-10] relatively small scales in median row vs. 8 large scales), in having more gill rakers on the ceratobranchial of the first gill arch (9-10 vs. usually less than 9) and in lacking conspicuous dark nape markings. Andinoacara rivulatus differs from A. stalsbergi in having thinner lips and dark flank scale centers, which form longitudinal rows (vs. flank scales edged with dark, forming a reticulate pattern). It differs from A. blombergi in having fewer scales in the E1 row (24, rarely 23, vs. 25, rarely 26 and exceptionally 24), and in having a broader head and interorbital width. Live specimens differ additionally from both species in having white or orange dorsal and caudal fin margins (vs. always white), and the margin of the caudal fin being broadened (up to about one third of the entire fin length) and somewhat washed out against the proximal part of the fin in adult males (vs. narrow and sharply defined; compiled from Musilová et al, 2009, Wijkmark et al, 2012 and personal observations).
Size: The lectotype, which is the largest specimen of the type series, measures only 72.1 mm SL and 96.9 mm TL (Wijkmark & al. 2012). The largest specimen examined by those authors was 123.3mm SL (extrapolated TL about 165mm), Eigenmann (1922) recorded a maximum TL of 207mm for his material. However, from field and aquarium observations, males are known to attain up to almost 30cm TL. Sexual maturity is usually reached (in aquarium) at about 8-10cm TL, but sometimes much smaller fishes may be fully colored and sexual active. Perhaps this is the result of overcrowding of raising tanks, but there are indications that stunted growth occurs also in the wild (Wijkmark & al. 2012).
Sex dimorphism: Females stay about 20% smaller than males, their soft dorsal and anal fin rays are less extended, and the tendency to develop a nuchal hump is less marked. Males are in general more brilliantly colored, particularly the greenish-golden markings of the body scales and the orange or white fin margins are much more pronounced. The spiny part of the dorsal fin shows a distinct pattern of oblique streaks in males but almost plain in females. Finally, females have the blue markings on the lower part of the head often (but not always) confluent to plain blue areas.
Common names: Goldsaumbuntbarsch (commercial, Deutsch), Green Terror (commercial, English), Orangesaumbuntbarsch (commercial, Deutsch), Vieja (native, Español).
Type locality: Andes of western Ecuador.
Distribution: Andinoacara rivulatus is widespread in western Ecuador, from the foothills of the Andes to the Pacific Coast and from the Rio Chone and Portoviejo drainages in the north to the river systems draining into the Golfo de Guayaquil (mostly the greater Guayas drainage), including also Rio Zarumilla and Rio Tumbes in the extreme northwest of Peru. Records from more southern localities in Peru are referable to A. stalsbergi, those from the Esmeraldas drainage to A. blombergi.
Niewenhuizen (quoted by Stawikowski & Werner 1998) observed the species in thermal waters in Budapest and in the vicinity of lake Balaton (Hungary). The status and ID of specimens found in the upper Amazon drainage in Ecuador is unknown, see comments.
Habitat: Stawikowski & Werner (1998) found Andinoacara rivulatus in a wide range of riverine habitats, from the clear, fast flowing mountain streams to residual pools, weedy ditches and the broad, turbid lower courses of large rivers. It was observed over bottoms of gravel, scree, sand, mud or sunken leaves, among wood or aquatic plants. Andinoacara rivulatus was found in the shallow littoral zone as well as in the stronger currents and deeper waters in the middle of the river. Large specimens of more than 20cm TL were seen exclusively in deep water. The water parameters determined by Stawikowski & Werner were quite uniform (temperature about 25°C, 1-2°C less in higher regions; pH about 7; 3°KH; at most 1°dGH).
Localities: Río Quininde (Ecuador, native).
Feeding: No data available. Judging from aquarium observations, Andinoacara rivulatus is carnivorous, probably feeding mostly of aquatic invertebrates, but also capable to prey on small fish.
Breeding: Andinoacara rivulatus is a monogamous substrate brooder which seems to prefer open, horizontal spawning sites. In aquarium, this is usually the upper side of a flat stone or a piece of wood. As yet, I have never seen a pair spawning in a cave. The number of eggs varies between 200 and over 600, depending on the size and condition of the female. The eggs are almost exclusively tended by the female while the male guards the territory more or less ardently. The larvae, which will hatch about 60-64 hours after spawning (at 26°C; personal observation), are deposited in comparatively small pits constructed between rocks or at the roots of plants and are moved several times. The male participates in such activities, otherwise the allocation of duties remains the same until the fry start to swim at about the fifth day after hatching. Both parents guard the fry and escort them trough the territory. In case of a real or supposed danger such as an approaching fish or even person the male starts a vigorous attack, while the female first gets the fry out of danger. The brood care may last several weeks.
Aquaristics: In Germany, Andinoacara rivulatus appeared in the hobby in 1979 or 1980. Because of the striking coloration and impressive appearance, it enjoyed a rapidly growing popularity in the hobby, and still it is one of the most common larger cichlids in the aquarium fish trade. Data from other countries are highly welcomed.
Andinoacara rivulatus is not overly demanding with regard to water parameters and food. It eats no plants and does not dig very much when preparing to breed, so there‘s no need to do without plants. However, it certainly cannot be regarded as a peaceful cichlid. Its character is more reminiscent to that of Middle American cichlids than to that of the most east-Andean ‘Acaras‘, especially breeding fish are very aggressive and therefore difficult to keep together with other cichlids. Nevertheless this is possible, provided the tank is large enough (at least 150cm), allows the demarcation of territories and the accompanied species is able to assert.
The intraspecific aggressiveness is also not to be underestimated. The formation of pairs is often accompanied by fierce biting and jaw-locking, especially if the partners are similar-sized. Usually, these quarrels die down until spawning, and once the eggs are laid, the fish will attend to their brood in tolerable harmony. However, a loss of the offspring often leads to even more violent fights resulting in serious injuries of the weaker fish. Older fish that have several times bred successful together are more peaceful to each other, which allows keeping and breeding them in a comparatively small aquarium, however the fry should not be raised in the same tank. Some characids large enough not to be taken for food are recommended to decimate the offspring in a natural way.
If raising of young is desired, some of them (not all!) should be moved in a separate tank. It is not necessary to raise several hundreds of them, 30-50 are more than enough. Otherwise, even a large aquarium would be overcrowded sooner or later, and the growth and quality of the young would be unpaired more and more, not to mention the problem to sell or even give away them all.
Conservation: Andinoacara rivulatus is not evaluated by the international union for the conservation of nature in the iucn red list of threatened species.
Comments: Andinoacara rivulatus has long been considered conspecific with the species described as A. stalsbergi for the insufficient knowledge or disregard of the characters, which make it now so easy to distinguish between these two species. In other words: nobody knew that the Ecuadorian and Peruvian Andinoacara were distinct species. When the latter was introduced in the early 1970s, it was identified in accordance with the knowledge of that time as Aequidens rivulatus.
When the ‘Goldsaum‘ cichlid appeared in the hobby, it was immedially recognized as a distinct species. However, since absolutely nothing was known about its origin, the species remained unidentified and was referred to as Aequidens sp.. Werner & Stawikowski (1985) were the first to discover that in Ecuador, from where Andinoacara rivulatus and all its synonyms have been described, only the ‘Goldsaum‘ occurs. Therefore they concluded that the ‘Goldsaum‘ was A. rivulatus and the Peruvian ‘Silbersaum‘ an undescribed species.
In more recent years, the identity of Andinoacara rivulatus has been questioned again. Alf Stalsberg (Norway), and later also other aquarists from North Europe and Germany, did collect a slightly different fish in the Rio Esmeraldas drainage, Ecuador. From Kullander‘s identification of this fish as A. rivulatus and the erroneous assumption that Rio Esmeraldas is the type locality, the conclusion was drawn that this was the true A. rivulatus, and the ‘Goldsaum‘ was a species of its own, for which sometimes the name Andinoacara aequinoctialis was used. However, these conclusions are untenable for the following reason: When separating Acara aequinoctialis from Acara rivulata, Regan (1905) restricted the latter to the largest of five supposed type specimens, while the four remaining were designated as types of the former. Normally, such an action would have to be regarded as a lectotype designation for A. rivulata. However, a lectotype can only be selected from syntypes, and we (Schindler & Morgenstern 2010) have found out that the specimen in question does not belong to the type series of Günther‘s Chromis rivulata. Therefore, Regan‘s action is invalid and the four syntypes of Acara aequinoctialis retain their status as syntypes of C. rivulata, rendering the former an objective junior synonym, which must not be used for a supposedly different species. Wijkmark & al. (2012) have confirmed these findings and have designated the largest of the four specimens in question as lectotype for both nominal species, thus consolidating the objective synonymy.
The type locality of Andinoacara rivulatus is known no more precisely as "Andes of Western Ecuador" (as per title of the original description). According to Wijkmark & al. (2012), a search for more detailed locality data was not successful. However, I was able to retrace Fraser’s itinerary, chiefly by means of ornithological literature (Morgenstern, in prep.). Most of his collections were made rather high up in the Andes, but the freshwater fishes sent along with the types of Andinoacara rivulatus must have been taken at lower elevations. The only station in the Andes, were Fraser could have reached such areas, was Pallatanga on the upper Rio Chimbo, but more likely the material was collected at Babahoyo on the river of the same name. Both Rio Chimbo and Rio Babahoyo are major tributaries to Rio Guayas. These findings provide further support for the identification of the ‘Goldsaum’ cichlid as the ‘true’ Andinoacara rivulatus.
Bleher (unpubl.) and Stalsberg (2010) collected a similar form in Rio Nagaritza (Rio Zamora system, Upper Amazon drainage, southwestern Ecuador). It remains to be determined if this is a natural occurrence or the result of a translocation, and if these specimens are referable to Andinoacara rivulatus. Photographs published by Stalsberg (2010) indicate, that it differs at least in the coloration of the caudal fin margin.