Uaru Fish -Cichlids of the Americas

At one time the uaru fish was called the poor man's discus" - but not any more.

Throughout the 1960s and ’70s, when only wild discus were available and usually sold for exorbitant sums of money, the uaru (pronounced “wahroo”) or triangle cichlid fish was often referred to as the “poor man’s discus” — they were readily available as juveniles and subadults at less than one-third the price of wild discus, and their body shape and habits mimicked those of discus. These days, with the proliferation of discus hatcheries and the ready availability of reasonably priced captive-bred individuals, the discus might be more correctly called the “poor man’s uaru!”

Although sporadically bred, the availability of either captive-reared stock or, rarer yet, wild imported uaru from Brazil, has nose-dived. Not surprisingly, their prices have gone up dramatically. Although lacking the brilliant iridescence of discus fish, uaru nevertheless remain highly desirable cichlids because of their interesting behavior and difficulty in spawning.

How Many Uaru?
In 1840, Johannes Heckel erected the genus Uaru and further described the species amphiacanthoides, the large, brown pancake-like cichlasomine commonly sold as the “wahroo” or triangle cichlid in the hobby. Rachow (1927) reports that the genus name derives from the native name for this fish: uara ura, which he suggests means “like a mirror,” presumably referring to the fish’s dinner-plate body shape.

Further, he suggests that the species name amphiacanthoides means “resembling Amphiacanthus, a genus of about 30 species, chiefly herbivorous fishes from the Indian and Western Pacific Oceans.” This marine genus is now known as Acanthurus, the surgeonfish, which Uaru species resemble both in body shape and in their preference for vegetable matter.

Most hobbyists are probably familiar with uaru. In addition to their highly compressed, saucer-shaped bodies, which they share with discus fish (and, to a lesser extent, severums), adults are notable for the conspicuous large black irregular triangular or wedge-shaped marking that extends along their flanks — just below the lateral line from the insertion of their pectoral fins back to the base of the tail fin. In addition, adult uaru sport a black spot or bar on the tail base, and a black “eyebrow” marking just above and behind their eyes (they remind me of Groucho Marx’s eyebrows).

The base coloration is a pleasing brown that lightens to cream along the belly and chest. The unpaired fins are dark and often marked in black with iridescent blue lines, particularly on the spines of the anal fin and along the the margins of the pelvic fins. Like discus fish, the eyes are usually bright red. Unlike discus and more like severums, the “pancake” body is often quite thick.

Uaru can grow to at least 12 inches at full maturity. They hail from the Amazon and its tributaries, principally in Brazil (e.g., the Rio Negro, and Rio Branco), as well as the Rio Tocantins/Rio Xingu system, and can often be found alongside discus and freshwater angelfish (according to Sterba 1962). Not surprisingly, their requirements in the aquarium are nearly identical with those of discus.

As is often the case, Uaru amphiancanthoides was described independently, but later, by a host of ichthyologists. Synonyms include: Pomotis fasciatus Jardine 1843, Uaru obscurum Günther 1862, and Acara imperialis Steindachner 1879. Steindachner (1980) later waffled and put imperialis into the genus Heros (severum) and then Astronotus (oscar).

Incidentally, Pellegrin (1904), in reexamining and commenting on Steindachner’s Uaru (Acara) imperialis, notes that the largest specimen in his series was less than 2 inches. This would probably account for the coloration description (“5 lines of small, sky-blue spots on body”) typical of juvenile U. amphiacanthoides (see below). There are, however, at least two additional species of UaruU. fernandezyepezi, described by Stawikowski in 1989, and a third, an apparently undescribed species.

Uaru fernandezyepezi (named after by the Venezuelan ichthyologist Agustin Fernandez Yepez, who died in 1977) was first caught by Hans Kopke in 1988 in the Rio Atabapo, in eastern Colombia. This individual measured 9½ inches in length. It apparently is rare in nature (Andersen 1994), but has been recently imported live into Europe.

If the photo of this freshwater fish that appears in Anderson (1994) is accurate, U. fernandezyepezi is very unlike U. amphiacanthoides. Instead of a large black triangle against a brown background, it apparently expresses a series of four dark vertical bars starting at mid-body, back to the tail and extending from the dorsal fin ventrally down to the anal fin. According to Andersen (1994) the fins are light brown and the dorsal fin is edged in red.

The third, aseemingly undescribed species, was pictured in Stawikowski and Werner (1988; page 61) and again in Staeck and Linke (1985; drawing on page161). I have had four specimens of this fish once myself (1987).

Rather than triangles, this species has large black rectangles on its flanks that begin just at, and not below, the lateral line, and the blotch on the base of the tail is a vertical band. The black eyebrow is lacking. There are also some indistinct vermiculaform markings on the snout, reminiscent of severum (H. severus). I have no location data on my own specimens, but neither do Stawikowski and Werner (1988) nor Staeck and Linke (1985 ). Regrettably, I never bred the fish, lost them and have never seen them again.

In October 1996 I received a photo from Laif DeMason, proprietor of Old World Exotics in Florida, for identification purposes, which was published in Cichlid News (January 1997, page 36). It is clearly either U. fernandezyepezi or a fourth undescribed species. It’s reportedly from Brazil, making the former identification unlikely.

In this photo, the fish displays two vertical black bands, one on the base of the tail and one about three-quarters of the way down the body (halfway between the middle and the base of the tail of the fish). There is a third indisdinct vertical band on the midline culminating in a dark black spot just below the insertion of the dorsal fin. Unfortunately, for this hobbyist, the fish, which had turned up at another Florida importer, had long since been sold.

Uaru in the Aquarium
According to Sterba (1962) and Holly et al. (1941), this fish was first imported into Hamburg, Germany, in 1913. I found a picture (dated 1916 and signed by the artist) and short account of the “Keilfleckcichlide” (wedge-spot cichlid) in Rachow 1927 (German book, translated into English), and a much longer account, again in Holly et al. (1941; German), in which their successful spawning is discussed. However, this fish is conspicuously absent from the American hobby literature.

I can find no article or reference to it in either Aquatic Life (Vol. 1 to 15, 1915 to 1932) or in The Aquarium (Vol. 1 to 17, 1932 to 1948), the preeminent American hobby magazines of their time. No entry ever appears in Innes’ Exotic Aquarium Fishes right through the 19th edition (revised) published in 1964. Recall that the discus, also described by Heckel in 1840, had made it into the American and German hobbies by the 1930s (see Leibel 1996b), so the uaru fish was definitely ignored by the American hobby despite being a long-term and welcome fixture in the German hobby. Perhaps the subtlety of its brown and black coloration was lost on American hobbyists more taken with the iridescent incandescence of discus. I would submit that this remains true, even today.

Yet, Uaru amphiacanthoides is no less charming and interesting than either the discus or the angelfish, and, in some respects, is even more interesting. Like discus, U. amphiacanthoides contact feeds its young. Unlike discus, this is not absolutely necessary for the successful rearing of fry, and is why uaru fish were successfully spawned well before discus.

One unique aspect of their growth and development is that uaru have a distinctively different juvenile color pattern that changes dramatically as the fish reach sub-adulthood. Initially, the chocolate-brown base color is punctuated at regular intervals by rows of white spots — there are no hints of the black flank wedges or of the Groucho eyebrows. This juvenile color pattern is not unlike that of the Tanganyikan cichlid Tropheus duboisi.

As the fish nears 2 inches or so, the pattern begins to break up: the spots enlarge and the ground color lightens, until the fish transforms (at about 3 to 4 inches) into the adult pattern. (So too, T. duboisi fry lose their beautiful spot pattern and ultimately develop a white or yellow vertical bar in their midsection.) This colorational metamorphosis is one of the added joys of obtaining and raising uaru juveniles to adulthood. As Sterba (1962) wrote, uaru fish are best treated like discus in the aquarium. I refer you back to my article on wild discus in this magazine (Leibel 1996b) for details as to how to do so.

In summary, however, they need large aquariums (about 50 to 125 gallons) with well-maintained water. They should be kept warm (84 to 88 degrees Fahrenheit) and there should be plenty of aeration. Although soft, acid water is probably beneficial, it is not apparently necesssary: Nini Schultz (1988) was able to spawn them repeatedly and successfully in water with a pH of 7.2, with slight hardness (120 parts per million).

They can be shy, so shelter in the form of submerged bog wood, along with dim lighting, is recommended. Provide some flat rocks to hold the egg plaque if spawning is a desired outcome.

Unlike discus, live aquatic plants should be omitted as these are enthusiastic herbivores! In fact, one of the requirements for successfully maintaining uaru is to provide adequate vegetable materials in their diets. This can be romaine lettuce, parboiled zucchini or any of a number of Spirulina-based disc foods (e.g., Wardley, Hikari) and flake foods (e.g., Tetra Dorogreen). Spinach is probably not a good idea on a regular basis because of the toxic oxalic acid found in their leaves. Excess duckweed, Java moss and water sprite works well, too.

Of course, these should supplement a rich base diet of prepared, frozen and even live foods. Johnson (1992) fed live earthworms, mealworms and trout chow, and no vegetable material directly. Quarles (1997) also omitted vegetable material and fed a mixture of blended beef heart and shrimp as a staple, with blackworms and adult brine shrimp as an additional treat. Both were able to spawn the fish successfully.

Breeding can be touchy, and actually raising fry harder still. For starters, you need a pair, which is easier said than done! While some, including Sterba (1962) and Loiselle (1992), suggest that (the only way) one can sex adult specimens by “venting” them (turning them over and inspecting their urogenital openings), I have seen too many errors made by experienced hobbyists with South American cichlids to take this approach seriously. As often as not, when the tubes actually come down during a spawning, “George” becomes “Georgia.” Which is okay, except that “Martha” may really be “Martha” — two spawning females! This is another cichlid fish, like angelfish and discus, in which compatible all-female couples form and spawn, exchanging roles as egg-layer from spawn to spawn.

Loiselle (1992) reports that some breeders maintain that males have somewhat more pointed soft dorsal and anal fins than females, and a more rounded cranial profile, but that these differences are subtle. It has been suggested (Johnson 1992) that uaru fish can be sexed on the basis of eye color (red for males, orange for females). However, it has been the experience of many successful uaru breeders that this system does not work (at least not for their fish).

So, the recommendation? You guessed it — raise four to six or eight juveniles. Or, if adults are all that are available, buy several. As Schultz (1988) describes, when two fish constantly swim together (she started with four adults), pair formation has occurred.

Johnson (1992) describes the courtship behavior as consisting of lip-tugging, side-by-side swimming and mutual spawning site preparation. Again, all-female pairs may form, but with additional fish you have the opportunity of mixing and matching until you get fertile eggs.

The other major problem in breeding uaru fish is that they are notorious egg eaters. Often, one parent becomes the chronically offending partner. You can either try to change partners or pull the rock and incubate the eggs artificially, as per angelfish (see Leibel 1996a). Johnson (1992) did just this with impressive success.

I remember way back when I was a member of the Elm City Aquarium Society (New Haven, Connecticut) circa 1975. One member, Sue Rastad, an able aquarist who, like Nini Schultz, could spawn anything she put her mind to, was routinely getting uaru eggs only to have them eaten within a few days (and prior to hatching). She told us that she used to stand guard over the eggs and beat the offending parent on the head (gently) with a net if he/she approached the clutch, until she felt the eggs were old enough to snatch and rear artificially!

Another suggestion (made by Eberhard Schulze, 1988, in his book on discus) is to cover the spawn with wire mesh (held in place by suction cups) that will keep the parents from getting at the spawn but allow them to fan the eggs to prevent fungus. Nini Schultz (1988) also reported that with the light kept on continuously, the spawners did not eat their eggs for at least three days (they hatch on day four). Incidentally, uaru fish, like discus and angelfish, will spawn every five to seven days for long periods if the eggs are eaten or removed (N. Schultz 1988).

Nini Schultz (1988) found, as is the case for discus fry, that newly hatched brine shrimp were too large for newly hatched uaru. Instead, and taking a cue from commercial discus hatcheries, she fed the free-swimming fry powdered (baker’s) egg yolk four times a day for the first five days, at which time she switched them to newly hatched brine shrimp.

Johnson (1992), in contrast, reported that he was able to feed newly hatched brine shrimp nauplia immediately. So did Quarles (1997), but the size of Artemia nauplii varies dramatically depending on the origin of the eggs. Azuma (1973) reported that either brine shrimp or hard-boiled egg squeezed through a cloth could be used as a first fish food for the free-swimming, foraging fry.

Spawns are typically small for such a large fish, about 100 or so eggs (Stawikowski and Werner 1988). However, Johnson(1992) reported consistent spawn sizes of 200 to 300 eggs, once the breeders got going, for several spawnings. Azuma (1973) reported repeated spawns of 500-plus eggs. Quarles (1997) reports spawn sizes of “about 500 eggs.”

Schultz (1988) raised 96 in her first successful batch, with no mortalities. She raised many subsequent broods, and regularly supplied one East Coast wholesaler with juveniles for several years.

Incidentally, she noted that growth was extremely rapid. After two weeks in a 10-gallon aquarium the fry were moved to a 20 gallon for three more weeks, and then a 40-gallon aquarium — with 20-percent water changes done twice a week throughout. At 10 weeks of age, the “babies” had reached 2 inches!

This is good news if you intend to breed uaru commercially. A productive pair of uaru is a gold mine, given the constant demand for these fish and the small number of fry they produce despite their size.

Incidentally, although they can get aggressive with each other, uaru can be successfully kept in community situations with fish that share their maintenance requirements and are bigger than the uarus’ mouths. In fact, Nini Schultz’s uarus spawned in a 125-gallon community aquarium! See Leibel (1996b) for tankmate suggestions.

Even if you are not intending to breed them, uaru are worth keeping. If not for their subtle coloration (which I, for one, find attractive!), then for their personalities. In many ways, uaru are like oscars (Astronotus sp.) behaviorally. That is, they are deliberate in their movements and even appear to be thoughtful. It would seem that with bigger size goes bigger brains, at least in New World cichlids.

Andersen, K. 1994. Colombia: Back to Paradise. In The Cichlids Yearbook Vol. 4, A. Konings, ed. Pp. 78-83.
Azuma, H. 1973. Spawning the triangle cichlid, Uaru amphiacanthoides. Tropical Fish Hobbyist (TFH) Vol. 22 (December):4 et seq.
Holly, M. A. Rachow and H. Meinkein, 1941. Die Aquarien Fische (looseleaf). Suppl 5. Pp. 831/832. (in German)
Johnson, D. 1992. Spawning the “almost” discus. Aquarium Fish Intl. (AFI) 5(3):60-63.
Leibel, W., 1996a. Goin’ South: The Pancake Cichlasomines, Part 1 (Angelfish). AFI X(X):XX-XX.
Leibel, W, 1996b. Goin’ South: The Pancake Cichlasomines, Part 2 (Discus). AFI X(X):XX-XX.
Loiselle, P. 1992. Cichlid Forum: Almost a discus. AFI 4(9):5-6.
Pellegrin, J. 1904. Etudes des poissons de la famille des cichlides (in French). Mem Soc Zool France 16:41-399.
Rachow, A. 1927. Tropical Aquariafish Catalog (in English). Aquarienfisch Im-und ExportCo., Hamburg, Germany. Pp 152.
Schulze, E. 1988. Discus Fish, The King of All Aquarium Fish. Discus Limited. Bangkok, Thailand. Pp 139.
Schultz, N., 1988. Breeding the Uaru amphiacanthoides. The Reporter: Bull North Jersey Aqua Soc. July:XX-XX.
Staeck, W. and H. Linke. 1985. Amerikanische Cichliden II GrosseBuntbarsche (in German). Tetra Verlag, West Germany. Pp. 164.
Stawikowski, R. and U. Werner. 1988. Die Buntbarsche der Neuen Welt:Südamerica (in German). Reimar Hobbing Verlag, West Germany. Pp. 288.
Sterba, G. 1962. Freshwater Fishes of the World (English translation). Pet Library, Ltd., New York. Pp. 837.
Quarles, J. 1997. Uaru amphiancanthoides: The Poor Man’s Discus. TFH 45(7)(March):116-123.

Share On Facebook
Share On Twitter
Share On Google Plus
Share On Linkedin
Share On Pinterest
Share On Reddit
Share On Stumbleupon
Article Categories:
Fish · Freshwater Fish