Taxonomy & naming
The Amatitlan cichlid was described by the German-born British ichthyologist Albert Günther in 1864 as Heros guttulatus, from a single specimen (the unique holotype, BMNH 1864.1.26.298) taken on the Pacific coast of Guatemala, probably from Lake Amatitlán. The epithet — 'finely spotted' — refers to the speckling on the body. As with the rest of the Middle American 'Cichlasoma', it spent generations in that catch-all genus and was later moved through Paraneetroplus before settling in Vieja, where the Catalog of Fishes lists it as valid (Vieja guttulata). Its taxonomic history is bound up with that of the Atlantic-slope Vieja fenestrata: several twentieth-century authors treated guttulata as a synonym of fenestrata, but the two are now recognised as separate species on opposite slopes of Mesoamerica, a distinction supported by Morgenstern's (2016) re-examination of the type material. It sits in the Neotropical subfamily Cichlinae among the heroine cichlids, and the modern herichthyin revision (McMahan et al. 2015) and later checklists retain it in Vieja.
Morphology
Vieja guttulata is a tall, stout, strongly compressed cichlid; FishBase gives a maximum of about 12 in, placing it among the larger species in the genus, and big males develop the steep forehead and nuchal hump characteristic of Vieja. The species takes its name from the fine spotting that can pattern the body, set against a ground colour that ranges from olive and silvery-grey to a pearly, faintly bluish or greenish sheen, often with warmer tones on the head and breast in conditioned fish and a dark spot at the base of the tail. As in most Vieja the colour deepens and the markings sharpen with maturity and spawning condition, while subadults are plainer and more uniformly silvery. Sexual dimorphism follows the genus pattern: males grow larger and carry the heavier forehead and hump, ripe females are deeper-bodied; the sexes are difficult to separate outside breeding condition.
Habitat
Uniquely among the genus, Vieja guttulata is a fish of the Pacific (rather than Atlantic) slope of Mesoamerica. The Catalog of Fishes gives its distribution as the Pacific slope of southern Mexico, Guatemala and El Salvador, and its type locality is Lake Amatitlán, a warm lowland lake near Guatemala City. It occupies warm, slow, low-gradient water: lakes, lagoons and the sluggish lower reaches of Pacific-draining rivers, over soft mud and sand among submerged wood. In-situ and aquarium-derived chemistry point to warm, near-neutral to alkaline, moderately hard conditions, consistent with the volcanic and calcareous lowland country of the Pacific coastal plain. Its Pacific-slope range distinguishes it sharply from the Usumacinta–Grijalva and Papaloapan Vieja, and makes it a biogeographically notable member of the genus — a lineage that crossed, or was left on the far side of, the Mesoamerican continental divide.
Feeding
Vieja guttulata is a large omnivore with the strong herbivorous and detritivorous bias characteristic of its genus. It works the soft bottom and submerged wood of slow lowland water for plant material, algae, detritus, fallen seeds and fruit and the small invertebrates living among them, using robust jaws suited to tearing and grazing vegetation rather than pursuing prey. In the lake and river community it functions as a large-bodied grazer and processor of plant detritus rather than a predator, taking animal food opportunistically as all big cichlids do. The vegetable-leaning diet is the practical key to keeping the species in good health.
Mating
The species is a monogamous, biparental substrate spawner that becomes territorial as a pair forms. Outside breeding it is reasonably tolerant for so large a cichlid, but a settled pair claims and defends a territory around a chosen spawning surface, and — as throughout the genus — pairing can be combative, with a male liable to harass an unready female, so a well-matched pair in adequate space matters. Courtship follows the heroine pattern of lateral displays, jaw-locking 'wrestling', quivering and the joint cleaning and inspection of a flat hard surface, accompanied by the deepening of body colour and the female's increasing girth as she ripens.
Breeding
Vieja guttulata is a biparental, open substrate spawner. The pair cleans a flat hard surface and the female lays her eggs on it in the open, after which both parents share guarding and fanning; after hatching the wrigglers are typically moved to pits excavated in the substrate and the free-swimming fry are led about and defended fiercely by both parents. Precise wild fecundity figures are not well documented, but the genus typically produces several hundred fry per spawning, and large females of this comparatively big species can be expected toward the upper end of that range. In aquaria it spawns in the standard biparental manner once a compatible pair, a flat spawning site and a digging substrate are provided; as with the rest of Vieja, the practical challenge is managing the pair's spawning aggression rather than any difficulty in obtaining eggs.
In the aquarium
Vieja guttulata is a hardy, robust large Central American cichlid kept by enthusiasts of the group but uncommon in the general trade, in part because of its Pacific-slope origin and limited export. At an adult size around 12 in it needs a large tank: a footprint of roughly 180 × 23.5 in (about 120 US gal) is a sensible minimum for a single fish or a settled pair, with more space advisable if other large fish share the aquarium. Water chemistry is undemanding within the species' natural envelope — a near-neutral to mildly alkaline pH (about 7.0–8.0), moderate hardness and a temperature of roughly 77–84 °F suit it well. As a big, messy feeder it needs generous filtration and substantial regular water changes, but not strong current; aim returns to break the surface for gas exchange.
Use a sand or fine substrate, since the fish digs, and furnish the tank with sturdy rockwork, roots and driftwood that provide cover and break up sightlines; décor must be stable, as an adult rearranges it. Rooted plants are largely futile with Vieja — they uproot and eat vegetation — so greenery is best treated as food or kept to tough, potted or floating species. Diet should respect the species' plant bias: spirulina and other green foods, blanched vegetables and quality vegetable-based pellets as the base, with frozen or live invertebrates as supplements rather than the staple; overfeeding rich protein is a common cause of digestive trouble and head-and-lateral-line erosion in big Vieja.
Temperament is robust but workable. Outside breeding the species is relatively even-tempered for its size and combines well with other large, sturdy Central American cichlids and big catfish or characins able to hold their own; nothing small enough to be eaten is safe. Aggression rises sharply at spawning, when a guarding pair can dominate even a large aquarium, so ample space, broken sightlines and the readiness to separate fish are the standard safeguards. The usual keeper mistakes are underestimating the adult size, overstocking and feeding too richly rather than any fussiness in the fish.
Conservation
The IUCN Red List assesses Vieja guttulata as Data Deficient (assessed 2018, published 2019), with the population trend recorded as unknown. The Data Deficient listing reflects genuine gaps in knowledge of the species' distribution, abundance and biology rather than a documented decline; it is recorded across a moderately broad Pacific-slope range from southern Mexico through Guatemala to El Salvador, but the published information is too thin to support a threat-based category. Its type locality, Lake Amatitlán, is a notably polluted lake near Guatemala City, and the Pacific coastal lowlands generally face the familiar pressures of deforestation, pollution, water extraction and introduced tilapia — so localized declines are plausible even though the species' overall status cannot yet be judged. It carries no CITES listing and is harmless to humans. Better survey across its range, and clarification of how its populations relate to those of its Atlantic-slope relatives, are the obvious priorities.