Taxonomy & naming
Cichla mirianae was described by Swedish ichthyologist Sven O. Kullander and Brazilian ichthyologist Efrem J. G. Ferreira in their 2006 monograph "A review of the South American cichlid genus Cichla, with descriptions of nine new species" (Ichthyological Exploration of Freshwaters 17(4): 289-398). That revision was a watershed: until the early 2000s most authors recognized only two or three peacock bass, and Kullander and Ferreira resolved the genus into fifteen species, nine of them new, of which mirianae was one (a sixteenth, Cichla cataractae, was added from the Essequibo in 2020). The genus sits in the New World subfamily Cichlinae, tribe Cichlini, and the nomenclatural act is registered in ZooBank.
The species epithet is an eponym honoring Mirian Leal-Carvalho, a zoologist in the ichthyology department of the Museu Paraense Emilio Goeldi in Belem. The type material comes from Mato Grosso in the Rio Tapajos drainage; paratypes are held in collections including the Swedish Museum of Natural History (e.g. NRM 46003, an adult female). In the hobby the fish travels under the trade names "Cichla mirianae FOGO," "tucunare fogo," and "fire peacock bass"; tucunare is the broad Tupi-derived name for peacock basses throughout Brazil.
Morphology
Like all peacock bass, Cichla mirianae is an elongate, powerfully built cichlid with a large mouth and a notched dorsal fin, fusiform in profile and clearly shaped for fast pursuit. Its diagnostic pattern, laid out in the original description, is a reliable way to separate it from its relatives: juveniles carry a dark horizontal band along the flank plus three blackish, ocellated (eye-spotted) blotches down the middle of the body, appearing from roughly 3.5 in standard length. As the fish matures, the band breaks up into irregular black stripes that link the three ocelli and run back onto the caudal peduncle, and three faint vertical bars are present at all ages. There are 72-80 scales along the lateral line, which is discontinuous. The only close look-alike is Cichla orinocensis, which also bears three lateral ocelli, but mirianae is set apart by its horizontal band, which orinocensis lacks; the three-ocelli pattern and few, indistinct bars also distinguish it from heavily barred species such as Cichla intermedia, Cichla nigromaculata, and Cichla piquiti.
The trait that makes the species coveted is its color. Adults flush yellow to orange across the gill covers and ventral surface, and in the famous "fogo" (Portuguese for fire) fish this deepens into a vivid, glowing red on the throat and breast. Juveniles arrive in the trade with merely yellow bellies; keepers report the reds and oranges intensifying as the fish grow, often with the dominant individual coloring up first. Color and the brighter, more contrasting markings of breeding fish are the clearest sex-related cues, and males develop the heavier, blunter head profile and nuchal hump typical of mature peacock bass. Maximum size is reported inconsistently. The original description gives a largest examined specimen of about 12.5 in standard length, and FishBase lists a figure of 20.5 in SL; specialist suppliers describe wild fish reaching roughly 19.5 in total length, and rod-and-reel records from the Rio Tapajos run to about 27.5 in and 6 kg (roughly 28 in, 13.5 lb). The honest summary is that this is a large peacock bass of moderate size for the genus, smaller than the giant Cichla temensis but well beyond anything for a casual aquarium.
Habitat
Cichla mirianae is endemic to Brazil and to two adjacent shield-draining river systems in the state of Mato Grosso: the upper Rio Tapajos basin, where it occurs in the Juruena and Teles Pires rivers, and the upper and middle Rio Xingu. Kullander and Ferreira mapped it to these drainages, the IUCN assessment confirms the same restricted range, and aquarium documentation of adults traces them to localities such as Sao Felix do Xingu. This is a comparatively tight distribution by peacock-bass standards, and it is why the most prized wild "fogo" fish were historically collected from remote, hard-to-reach waters reached only by small aircraft.
The Tapajos and Xingu are classic clearwater rivers draining the ancient, nutrient-poor crystalline rock of the Brazilian Shield: transparent, relatively warm, soft and weakly acidic water, studded with rapids, sandbars, and white-sand margins. Peacock bass within these systems favor slower, sun-warmed water adjacent to the current, lagoons and lake-like backwaters off the main channel, and structure such as sunken wood and rocky margins from which to ambush prey. FishBase classifies the species as a benthopelagic freshwater fish of tropical lowlands. Because Cichla are visual hunters, the high water clarity of these shield rivers is not incidental to where they live; it is central to how they make a living.
Feeding
Peacock bass are the apex diurnal predators of Neotropical rivers, and Cichla mirianae is no exception. The genus hunts by sight in daylight and seldom feeds at night, which ties its activity tightly to water clarity and light. Adults are essentially piscivorous, taking smaller fishes in fast ambush strikes from cover or open water, with shrimp and other invertebrates rounding out the diet of younger fish; FishBase places the species near the top of the food web with an estimated trophic level around 4.3. The forward-projecting lower jaw and large gape let an adult engulf surprisingly large prey.
In its native rivers mirianae fills the role of a top predator, a control on populations of the small characins and other forage fishes that abound in the clearwater systems of the Tapajos and Xingu. That same predatory efficiency is exactly why introduced peacock bass have caused ecological problems elsewhere in Brazil and abroad, though mirianae itself is a narrow-range native rather than a notorious invader. Note that detailed, species-specific field studies of its diet and growth in the wild are thin; much of what can be said is inferred from the well-documented biology of the genus and from the original description, and is presented here on that basis.
Mating
Outside of breeding, Cichla are loosely social and often move in groups, especially as juveniles, and pairs form from within these aggregations as the season turns. Keepers who raise mirianae in groups describe them as among the more pugnacious peacock bass for their size: constant roughhousing, flaring, and chasing, usually as non-injurious sparring rather than serious damage, with at least a couple of individuals "playing" at any given time. This restless, combative energy is consistent across independent hobbyist accounts and is the backdrop against which pairs sort themselves out; a shoal of three or more spreads the aggression and leaves the fish calmer and bolder than a lone specimen or a mismatched pair, which tends to sulk and hide.
As a pair commits, the two fish intensify in color, the markings sharpen, and they begin to clear and defend a spawning site against the rest of the group. The heightened territoriality and mutual displays that precede spawning are the visible courtship; documented captive pair-bonding for this particular species is uncommon in English-language sources, but the behavior follows the standard Cichla pattern of a monogamous pair establishing and guarding a site together.
Breeding
Cichla are open, substrate-spawning cichlids with biparental care, and the broad outline of their reproduction is well established even where mirianae-specific observations are scarce. A pair clears and defends a site, lays a large clutch of adhesive eggs in the open or in a shallow depression, and both parents guard the eggs and then shepherd the free-swimming fry; clutches in the genus can run to several thousand eggs, and parents are notably aggressive in defense of the brood. The fry are herded as a dense school that the adults steer and screen from predators, a hallmark of peacock-bass parenting.
Documented captive spawnings of this particular species are uncommon in English-language sources, and the sheer adult size and the space a pair demands put deliberate breeding beyond most hobbyists; what is reported follows the standard Cichla pattern of a guarded open nest and biparental care of a fry school. In the wild, spawning is tied to the seasonal rhythm of these clearwater rivers, with reproduction concentrated around the transition into lower, warmer water when forage for the fry is abundant.
In the aquarium
This is a specialist's fish, and reputable suppliers say so plainly rather than dressing it up. An adult peacock bass of this size needs a tank measured in thousands of liters, not hundreds; growout tanks of 75-125 gallons are a temporary stage only, and the long-term home is a multi-meter system. Warm, clean, well-oxygenated water is essential, with strong filtration and current and very regular large water changes to cope with the heavy waste load of a growing predator; growout temperatures in the mid-to-upper 80s F (around 30-31 C) keep young fish active and feeding and help ward off the ich they are prone to when stressed or chilled. The species is prized above all for its color, the yellow-to-fire-red flush that gives the fogo its name.
The practical pitfalls are consistent across the hobby. Pellet-train as early as possible, because a fish living on whole-fish feedings fouls water fast; experienced keepers wean fish onto quality pellets by mixing crushed pellets into thawed frozen food, sometimes using fast-eating dither fish like silver dollars to create feeding competition. Avoid untreated live feeders, which import parasites and disease. Keep mirianae in a group of at least three or more rather than singly or in twos, both to diffuse their above-average sparring and to keep them confident and visible. Tankmates should be large, robust, and fast; small fish are simply food, and aggression spikes around feeding and spawning. None of this is beginner territory: the combination of adult size, predatory appetite, sensitivity to water quality, and an above-average temper means Cichla mirianae rewards experienced big-fish keepers and frustrates everyone else.
Conservation
The IUCN Red List assesses Cichla mirianae as Least Concern (assessed 7 November 2018, published 2022 by Brazil's Instituto Chico Mendes de Conservacao da Biodiversidade, ICMBio), with a stable population. The assessment describes the species as widely distributed within its basins, frequent and abundant, with no significant threats identified; it is taken as a food fish but not at a level flagged as a population-level concern, and a mosaic of protected areas falls within its range. (An older Cichlid Room Companion profile predating the assessment still lists it as not evaluated; the current IUCN status supersedes that.) So the bare status line is reassuring: this is not a fish in trouble.
That said, its restriction to the upper Tapajos (Juruena and Teles Pires) and the upper-middle Xingu places it squarely inside some of the most contested freshwater real estate in the Amazon. The Tapajos basin has been the target of an enormous proposed hydropower and industrial-waterway program, dams have been built on the Teles Pires, and the upper basin faces converging pressure from illegal gold mining (and its mercury), deforestation, and logging, documented by researchers and conservation groups including reporting compiled by Mongabay, International Rivers, and WWF. A clearwater, sight-hunting, structure-oriented predator is exactly the kind of fish that stands to lose from impoundment, turbidity, and altered flow: dams convert flowing shield rivers into reservoirs, mining clouds the very water clarity peacock bass depend on, and fragmentation isolates populations. None of these is presently documented as driving mirianae toward decline, and its own status remains Least Concern, but its narrow, shield-river range means the long-term health of this species is tied to whether the upper Tapajos and Xingu keep flowing clear.