Amatitlania sajica

The American ichthyologist William A. Bussing described this fish in 1974 as Cichlasoma sajica, from a series collected in a tributary of the Río Sierpe about two kilometres south of Palmar Sur, in Puntarenas Province on the Pacific slope of southern Costa Rica. The epithet is not Latin but an acronym: Bussing coined sajica for the Servicio de Asistencia Juvenil de Costa Rica (SAJICA), a youth-welfare body. Few small Central American cichlids have changed genera as often. Over the following decades the species was carried as Cichlasoma sajica, then Archocentrus sajica, then Cryptoheros sajica, before landing in Amatitlania. That last move followed the broad molecular and morphological revision of Middle American cichlids by Říčan, Piálek, Dragová and Novák (Vertebrate Zoology 66, 2016), which redrew the convict-group genera; some authors still use Cryptoheros, and the placement of the smaller convict relatives remains argued. Juan Jacobo Schmitter-Soto's 2007 revision of Archocentrus (Zootaxa 1603), which erected Amatitlania for the convict and its allies, is the other pillar of the modern classification. Eschmeyer's Catalog of Fishes and FishBase both list it as valid: Amatitlania sajica (Bussing, 1974).

Amatitlania sajica is a small, stocky, oval cichlid reaching about 3.5 in in standard length in males, with females smaller — FishBase gives roughly 3.1 in. The ground colour is pale grey to blue-grey or tan, and the defining mark is the one the hobby name records: a single bold dark vertical bar through the mid-body that, crossed by the dark horizontal lateral stripe, forms a 'T' or anchor shape. A second, fainter bar may show on the caudal peduncle. Breeding and displaying fish flush darker and the bar sharpens; sub-dominant or stressed fish can fade nearly plain. The fins carry a soft iridescent blue-green sheen, and ripe males develop reddish-orange in the dorsal and along the flanks. Dimorphism follows the usual convict pattern: males grow larger, with longer, more pointed dorsal- and anal-fin tips and, in old fish, a slight nuchal swelling; females are smaller and rounder-bodied. Unlike the true convict, Amatitlania nigrofasciata, the female sajica does not develop the strong orange belly patch, so the sexes are told apart more by size and finnage than by a colour badge.

The species is endemic to the Pacific slope of southern Costa Rica, living in small to medium rivers and clear forest streams of the Térraba (Grande de Térraba), Sierpe and neighbouring Pacific drainages — from near the type locality at Palmar south toward the Panama border. FishBase characterises it as a benthopelagic freshwater fish of warm lowland and foothill waters, with a temperature range of roughly 73–86 °F and a preference for neutral to mildly alkaline water (around pH 7 and above). Its streams are typically clear and moderately flowing over beds of sand, gravel and rounded stones with submerged wood and leaf litter, and the fish keeps to the structured margins where cover and spawning cavities are plentiful. This is a fish of low to moderate elevations rather than the high cordillera. Its range falls within the Pacific-slope freshwater fauna of lower Central America — broadly the Chiriquí ecoregion — a country of many short, steep rivers draining to the Pacific.

Amatitlania sajica is an opportunistic omnivore that forages over and through the bottom, taking aquatic insect larvae and other small invertebrates, plant matter, algae and detritus picked from stones, wood and the substrate. FishBase places it low on the food web as a small benthic feeder. Like its convict relatives it is a generalist rather than a specialist, which is part of why it transfers so readily to aquarium foods. In the stream community it works the rocky and woody margins, gleaning invertebrates and grazing the aufwuchs film — neither a dedicated piscivore nor an obligate substrate-sifter, just a small, busy, hardy omnivore.

The T-bar cichlid is a monogamous, biparental, pair-bonding cave-spawner, and by convict standards it is notably even-tempered — one reason it is a favourite first Central American for hobbyists who find the true convict too belligerent. A male and female form a pair and together choose and defend a cavity: a crevice between stones, a hollow under wood or an undercut bank in the wild, and a flowerpot, rock cave or length of pipe in the aquarium. Courtship is the standard cichlid repertoire of lateral display, fin-spreading and shared cleaning of the chosen spawning surface, with the female's deepening colour signalling her readiness. Territorial aggression sharpens around the nest, but outside of breeding and away from the cave sajica is among the more sociable convicts, less inclined to the relentless tank-clearing aggression of its larger cousins.

Amatitlania sajica is an easy, reliable biparental cave-spawner — a classic beginner's breeding project. The adhesive eggs, on the order of a hundred or so per spawn (smaller broods than the prolific true convict, in keeping with the smaller fish), are laid on the inner wall or roof of the chosen cavity. The female fans and mouths them while the male patrols and defends the surrounding territory. Eggs hatch in a few days at warm temperatures; the wrigglers are moved to pits and, once free-swimming, the fry are led out and guarded as a tight school by both parents, who shepherd them over the substrate and herd strays back. Parental care is extended and vigorous for so small a fish, and a settled pair will spawn repeatedly at short intervals. As with the other convicts, the main practical caution is that a breeding pair holds and defends its territory fiercely against tankmates despite the species' otherwise mild temperament.

The T-bar cichlid is a long-established, well-regarded aquarium fish, valued because it offers the full convict experience — pair-bonding, cave-spawning, devoted parental care — in a smaller, calmer package than the true convict.

Tank: a pair can be kept and bred in around 24–29 US gal (a 'three-foot' tank), larger if kept in a community. Décor should follow the home stream — a substrate of sand and fine gravel, plenty of rounded stones and bogwood arranged into caves and broken sight-lines, and one or more dedicated spawning caves (a flowerpot on its side or a short pipe works perfectly). Hardy plants survive better than with most diggers, though a spawning pair will clear a patch around the nest.

Water: match the warm, near-neutral to mildly alkaline Pacific-slope streams — temperature around 75–82 °F and pH roughly 7.0–8.0, with moderate hardness, good filtration and regular water changes.

Feeding: straightforward. This small, hardy omnivore takes quality flake and small sinking pellets readily, with frozen and live foods (bloodworm, brine shrimp, daphnia) and occasional vegetable matter rounding out the diet and bringing pairs into condition.

Tankmates: choose robust, similarly sized, non-timid fish — other moderate Central Americans, larger tetras, livebearers or armoured catfish — and give a breeding pair room, because even this mild convict turns sharply territorial around fry. The usual keeper mistakes are expecting community-fish manners during spawning and overcrowding the pair so it has nowhere to hold a territory.

The IUCN Red List assesses Amatitlania sajica as Vulnerable (assessed 21 September 2019). The species has a relatively restricted range on the Pacific slope of southern Costa Rica, and that limited distribution — combined with the familiar pressures on lower-Central-American freshwaters, from deforestation and the resulting sedimentation to agricultural runoff, water abstraction and introduced species — underlies the elevated category. Unlike the wide-ranging true convict, it is no habitat generalist, so localised degradation of its Pacific-slope rivers weighs more heavily. The species carries no CITES listing. It remains common in the aquarium trade, where it is bred in large numbers, so captive populations are secure even as the wild assessment flags concern for the fish in its native streams.