Taxonomy & naming
The fish was described by the American ichthyologist Carl L. Hubbs in 1936 as Cichlasoma aguadae, in his treatment of the fishes of the Yucatán Peninsula collected during the Carnegie Institution's expeditions. The type material came from an aguada — a shallow well or seasonal watering hole — at Tuxpeña in interior Campeche, Mexico, roughly 56 mi south and 25 mi east of Champotón; the holotype is held at the University of Michigan Museum of Zoology. For most of the twentieth century the species sat in the catch-all genus Cichlasoma alongside hundreds of other Central American heroines. The genus Mayaheros was erected by Říčan, Piálek, Dragová & Novák in 2016 to hold the Mayan-cichlid group — Mayaheros urophthalmus and its relatives — and the Catalog of Fishes (Fricke, Eschmeyer & Van der Laan) accordingly lists the species as Mayaheros aguadae (Hubbs 1936). Its validity, however, is the central question. Catalog of Fishes retains it only because it has never been directly checked against urophthalmus; the geometric-morphometric and molecular survey of Mayan cichlids across Yucatán by Mejía and colleagues (Copeia 2018) found the named forms to be phenotypic variants rather than separate lineages, and several of the old urophthalmus-group names have since been synonymized outright. Mayaheros aguadae thus persists as a nominally valid but unverified species — a name awaiting a formal revision.
Morphology
Mayaheros aguadae is a small-to-modest heroine cichlid; the type series and FishBase point to a fish maturing well under 6 in standard length, considerably smaller than the robust Mayaheros urophthalmus, which reaches over 12 in. The body is the typical oval, laterally compressed heroine shape, with a brassy-tan to olive ground colour overlaid by the lateral barring and dark flank markings characteristic of the Mayan-cichlid group. As in its relatives, the defining feature of the group is the conspicuous ocellus — a black, often pale-ringed eyespot — on the upper part of the caudal peduncle, the 'uro-ophthalmus' (tail-eye) that gives the parent species its name. Several dark vertical bars cross the flanks and can be flashed or suppressed with mood. Sexual dimorphism is slight, as it is throughout the genus: males average a little larger and develop somewhat longer dorsal and anal-fin tips, while ripe females are deeper-bellied; there is no dramatic difference in colour. Because the species has scarcely been studied apart from its original description, fine meristic and colour detail beyond the group-typical pattern is not well documented.
Habitat
The species is known from the interior of the Yucatán Peninsula on the Atlantic (Caribbean/Gulf) slope, in the karst lowlands of Campeche where surface water is scarce and largely confined to aguadas, cenotes and seasonal pools. The type aguada at Tuxpeña is exactly this kind of habitat: a shallow, standing or slowly-renewed body of water in limestone terrain, warm and turbid, fluctuating sharply with the wet and dry seasons. Like the rest of the Mayan-cichlid group it is a euryhaline generalist tolerant of the hard, mineral-rich, alkaline waters typical of the Yucatán's limestone aquifer, and the group as a whole ranges from fresh through brackish to nearly marine conditions in coastal lagoons. Water in these interior aguadas is warm (commonly mid-to-upper 20s °C), hard and alkaline (pH well above 7), and subject to wide swings in level, oxygen and clarity through the year. The species' apparent micro-endemism to the Campeche interior is at least partly an artifact of how little collecting has been done there; the broader group is found across the whole peninsula and the Gulf slope.
Feeding
No dedicated diet study exists for Mayaheros aguadae, but its membership in the Mayan-cichlid group places it among opportunistic omnivores with a carnivorous lean. Mayaheros urophthalmus, the best-studied member, is a generalist predator-omnivore taking small fish, crustaceans, aquatic and terrestrial insects, snails, detritus and some plant material, shifting its diet readily with what each habitat offers — a flexibility that underlies the group's success across such varied waters. A small interior-aguada fish like aguadae would be expected to work the bottom and margins for insect larvae, microcrustaceans, snails and organic debris, taking small fish and terrestrial invertebrates when available. The robust heroine jaw and pharyngeal mill suit a mixed diet that includes hard-shelled prey. Trophically the group sits in the mid-range of the food web as a flexible secondary consumer.
Mating
Reproductive behaviour has not been documented specifically for Mayaheros aguadae, but the Mayan-cichlid group is uniformly biparental and strongly territorial when breeding. In Mayaheros urophthalmus, pairs form a monogamous bond, clear and defend a substrate territory, and become markedly aggressive toward intruders during courtship and brood care; spawning is timed to the warm wet season when temperatures are reliably above about 75 °F and food is abundant. A pair courts with lateral displays, fin-spreading and substrate-cleaning over a chosen surface. There is every reason to expect Mayaheros aguadae follows the same template — a monogamous pair holding and defending a small territory in a shallow pool — though the confined, fluctuating aguada habitat would compress the breeding season into the months when water is present and warm.
Breeding
As with mating, breeding is undocumented for Mayaheros aguadae itself and is inferred from the group. Mayan cichlids are open substrate spawners: the pair lays adhesive eggs in rows on a cleaned hard surface — a flat stone, root, or firm patch of substrate — and both parents guard the clutch, fanning the eggs and later shepherding the free-swimming fry. Clutch sizes in Mayaheros urophthalmus run from a few hundred to over a thousand eggs depending on female size; eggs hatch in a few days at warm temperatures, and the wrigglers are moved to pits before becoming free-swimming. Parental care is extended — the pair guards the school of fry for several weeks, and Mayaheros urophthalmus is documented producing multiple broods through a long March-to-November season. A small-bodied form such as aguadae would lay a correspondingly smaller clutch, but the biparental, multiple-brood substrate-spawning pattern of the group is almost certainly retained.
In the aquarium
Mayaheros aguadae is essentially absent from the aquarium hobby as a named fish — it is not collected or traded under its own name, and what reaches keepers as 'Mayan cichlid' is overwhelmingly Mayaheros urophthalmus. Any husbandry guidance is therefore by extension from its better-known relatives, which are hardy, undemanding, and well suited to keepers who can manage their aggression. A pair would want a tank on the order of 55 US gal or more with an open sandy bottom, scattered rock and wood for cover and territory boundaries, and the hard, alkaline water of its limestone home (pH comfortably above 7, moderate-to-high hardness, temperature around 77–82 °F); the group tolerates a touch of salt and copes with a wide chemical envelope. The standing caution for the whole Mayan-cichlid group applies: they are robustly territorial and become genuinely combative when spawning, so tankmates must be sturdy and the tank large enough to defuse aggression. Feeding is trivial — they accept pellets, frozen and live foods readily. None of this is specific to aguadae, and a keeper should treat the name as a poorly-defined member of the urophthalmus complex rather than a distinct aquarium fish.
Conservation
Mayaheros aguadae has not been assessed in its own right by the IUCN Red List; the conservation evaluations in this group treat the Mayan cichlid as the single widespread species Mayaheros urophthalmus (assessed Least Concern), reflecting the same taxonomic uncertainty that surrounds aguadae's validity. As a nominally micro-endemic form of the Campeche interior, however, it would warrant a cautious read if it were ever confirmed distinct: the karst aguadas and cenotes of the Yucatán are small, isolated, and increasingly stressed by groundwater extraction, agricultural runoff, tourism development and the spread of introduced fishes (including African tilapias and other cichlids) across the peninsula. The broader Mayan-cichlid lineage is in no danger — it is abundant, adaptable and even invasive where introduced (notably in Florida) — but any genuinely range-restricted interior form would be far more exposed than its wide-ranging relatives. For now the honest statement is that the taxon is unassessed and its very distinctness unresolved.