Taxonomy & naming
Hermann Meinken described Apistogramma sweglesi in 1961 on the basis of living aquarium fish that had reached the German trade, rather than from a series of preserved museum specimens collected in the wild. This was characteristic of the post-war aquarium boom, when several Apistogramma were named from imports of uncertain provenance — Meinken himself would go on to coin Apistogramma klausewitzi (1962) and Apistogramma kleei (1964) in much the same way. The Catalog of Fishes gives the type locality verbatim as 'Letitia, Peru,' a misspelling that is universally read as Leticia, the Colombian Amazon port at the 'Tres Fronteras' where Colombia, Peru, and Brazil meet — the staging point through which a great many ornamental fish of that era were exported. The holotype's whereabouts are listed as unknown; the type material is lost.
The epithet is an eponym honouring Kyle Swegles, proprietor of the Rainbow Aquarium in Chicago, the dealer associated with importing the fish on which the name was based. The same collector is commemorated in the red phantom tetra, Hyphessobrycon sweglesi (Géry, 1961), described in the same year from the same Leticia-area trade — a useful cross-check that the honoree is indeed Swegles and not a coincidence of spelling.
Where sweglesi sits taxonomically is the crux. Mike Wise's working classification on apistogramma.com places Apistogramma bitaeniata — and therefore the fish 'sweglesi' represents — in the bitaeniata-complex of the bitaeniata-group within the agassizii-sublineage of the trifasciata-lineage. (The brief that prompted this profile suggested an alliance with Apistogramma pertensis and the agassizii line; the agassizii-sublineage placement is correct, but the closest tie is to bitaeniata, not pertensis.) Sven Kullander synonymized Apistogramma sweglesi with Apistogramma bitaeniata in 1986 and maintained that in his 2003 checklist, a treatment followed by Staeck (2003), Ready & Kullander (2004), and others. Against this, Uwe Römer's Cichlid Atlas tradition — Römer & Warzel (1998) and Römer et al. (2003) — argued the name should be retained as valid. The Catalog of Fishes lists both usages but currently treats the name as a synonym of Apistogramma bitaeniata. The honest bottom line is that 'sweglesi' is a contested aquarium-trade name with no surviving types and no confirmed wild population of its own; most modern ichthyology reads it as bitaeniata.
Morphology
Because Apistogramma sweglesi has no surviving type specimen and is generally regarded as the same fish as Apistogramma bitaeniata, its morphology can only be described through that species, and any 'diagnostic' features Meinken cited from aquarium fish are not independently verifiable. Apistogramma bitaeniata is a small, slender, elongate dwarf cichlid: FishBase carries a maximum of about 2 in standard length for the species overall, while careful hobby sources give breeding males to roughly 3 in and females to about 2 in total length, the larger figures reflecting well-grown aquarium males with their extended finnage. The body is laterally compressed and comparatively low-slung, the head pointed.
The defining mark is the pair of dark longitudinal stripes that give bitaeniata its name — a bold mid-lateral band running from the snout through the eye to the tail base, paralleled by a second, fainter supra-lateral stripe higher on the flank. Mature males develop a lyre-shaped (lyretail) caudal fin with the upper and lower rays drawn out into points, an elevated, serrated dorsal fin with the membrane often suffused yellow to orange, and blue-to-violet iridescence on the cheeks and lower body. The fish 'sweglesi' was simply this pattern as it appeared on imported stock, which is precisely why it could be mistaken for something new.
Habitat
No wild habitat can be tied directly to Apistogramma sweglesi, because the name rests on trade fish whose true collecting site was never recorded — the label 'Leticia' marks the export port, not a sampled biotope. The coordinates used in the Atlas for this entry (about 4° S, 70° W, near Leticia) are therefore a rough placement on the Amazon mainstem at the tri-border, not a verified locality, and they should be read as such; an earlier draft estimate placed it generically in the Rio Negro, which the documentary record does not support.
What can be said is drawn from Apistogramma bitaeniata, which is a blackwater specialist of the western Amazon. It ranges across the Peruvian, Colombian, and Brazilian Amazon — from the middle Marañón and lower Ucayali in Peru, through the Tres Fronteras region around Leticia, and downstream past Manaus toward the lower Madeira and Tapajós in Brazil. It favours slow tributaries, backwaters, and forest creeks where fallen leaves accumulate, sheltering in and feeding through the litter. The water is soft and acidic: hobby and field figures span roughly pH 4.5–7.0 (the lower, blackwater end preferred by wild fish), temperatures of about 72–84 °F, and very low hardness. These are shallow-water leaf-litter habitats; FishBase publishes no numeric depth band for the species, so the 0–3 ft recorded here is the documented depth of the forest creeks, backwaters, and litter margins it occupies rather than a sampled figure.
Feeding
As a member of the genus and, specifically, as Apistogramma bitaeniata, this is a micro-predator of the leaf-litter zone rather than a grazer. FishBase estimates a trophic level near 3.3 for bitaeniata, consistent with a diet of small benthic invertebrates — aquatic insect larvae, micro-crustaceans, and other tiny animals sieved or picked from the soft substrate and decaying leaves. In aquaria the fish takes readily to live and frozen foods such as Artemia, Daphnia, and bloodworm. There is no feeding information specific to 'sweglesi' beyond what applies to bitaeniata; any prey list attached to the name would simply be the bitaeniata diet.
Mating
The mating system, again read through Apistogramma bitaeniata, is the classic Apistogramma pattern of harem polygyny built around cover. A dominant male holds a comparatively large territory that overlaps the smaller territories of several females, each of which controls a spawning cavity. Courtship is driven by the female, who colours up — in bitaeniata to an intense yellow with the dark lateral stripe thrown into sharp relief — and solicits the male toward her cave. Males are the larger, more colourful sex with extended, lyrate fins; females are smaller and plainer outside breeding. Once a female is gravid and a cave is chosen, the male's role narrows quickly to fertilization and perimeter defence, while the female takes charge of the nest. No courtship behaviour is documented for 'sweglesi' as such.
Breeding
Apistogramma bitaeniata is a female-tending cave spawner, and this is the breeding biology that the name 'sweglesi' inherits. The female deposits a relatively small clutch — on the order of 40–50 eggs, often fewer — on the ceiling or wall of a sheltered cavity (a crevice, a cleft among roots, or in the aquarium a cave or inverted vessel), where the male fertilizes them. From that point care is essentially uniparental: the female tends and fans the eggs, which hatch in roughly three to five days, then guards the wriggling young and later leads the free-swimming fry through the leaf litter, frequently mouthing and shifting them. Guarding females become markedly, hormonally aggressive and will often drive the male well away from the brood, so in confined aquaria the male is sometimes removed. There are no breeding observations attributable specifically to Apistogramma sweglesi; everything stated here is the bitaeniata account.
In the aquarium
Keeping the fish behind the name 'sweglesi' means keeping Apistogramma bitaeniata, and Apistogramma bitaeniata is not a beginner's Apistogramma. Its wild chemistry is blackwater: pH in the 4.5–6.0 range, near-zero hardness (below 2° dH is not uncommon in Leticia-area creeks), and temperatures around 75–81 °F. Fish maintained in harder, more neutral water will survive short-term but typically fail to colour up fully, refuse to spawn, or develop the bloated or listless signs that precede a slow decline. This is a species where water chemistry is not a background parameter — it is the central management challenge. Reverse osmosis or deionised water remineralised to a conductivity of no more than 50–80 µS/cm is the practical standard for serious keepers. Commercially available blackwater conditioners (peat extract, Indian almond leaf tannins) reinforce the chemistry and appear to reduce stress; leaf litter itself acidifies the water gently over time and is strongly recommended both functionally and aesthetically.
A pair of Apistogramma bitaeniata can be accommodated in a well-planted 60-litre tank, but a harem setup — one male with two or three females, each with her own territory — rewards the keeper with far more natural behaviour and requires a footprint of at least 80 × 15.5 in, preferably larger. The tank should be shallow-ish (12–15.5 in depth suits a fish of leaf-litter shallows), and the floor covered in fine sand. Dense patches of low plants or floating cover (water sprite, hornwort) and an abundance of small caves — coconut shells, unglazed clay caves, sections of bamboo — give each female a defensible spawning site. Drifting leaves or a deliberate leaf-litter layer of dried oak, beech, or Catappa finishes the biotope and doubles as foraging habitat. The tank should be dimly lit; bright overhead light stresses these fish visibly.
Sexing is straightforward in adults: males are noticeably larger (to roughly 3 in TL), carry an elevated dorsal with drawn-out rays, and develop the characteristic lyretail caudal with extended tips. Females stay around 2 in TL, are less ornamented, and are the ones who flip to egg-yellow when guarding a brood — that carotenoid flush on the flanks and belly is the clearest gender cue the tank offers. Juveniles are harder to sex; waiting until the fish are eight to twelve weeks old usually gives enough size and fin dimorphism to work with.
Tankmates should be chosen with care. The bitaeniata complex is peaceful toward unrelated species that occupy the mid-water or surface — small tetras from the same blackwater region (pencilfish, cardinal tetras, hatchetfish) make natural companions and provide visual security for the cichlids without competing for caves. Avoid any boisterous or nippy fish, and avoid other cave-spawning dwarf cichlids in anything but a large tank. Catfish such as small Corydoras or Otocinclus can share the bottom, but give them refuge from the female during brood care — a guarding Apistogramma bitaeniata female will attack fish many times her size and can kill or stress tankmates that cannot escape. When running a harem the male will also periodically drive females; the layout must provide genuine visual breaks so subordinate females can avoid him. Common keeper failures include attempting this species in a standard 'community' with neutral tap water, overcrowding caves so that females cannot establish discrete territories, and removing the male too early (or too late) relative to spawning.
Because Apistogramma sweglesi is a contested synonym rather than a distinct taxon in trade, fish sold under this name are effectively Apistogramma bitaeniata — or are misidentified entirely, which has happened. The name is not commonly encountered in modern retail; most sellers now use bitaeniata. If you do find fish labelled sweglesi, treat them as bitaeniata in every husbandry respect and verify that they actually show the two-stripe pattern before assuming the identification. In the broader sense, this is a rewarding but genuinely demanding fish: the blackwater chemistry requirement is real, the harem dynamics are complex, and the female's brood-care aggression is fierce. Kept in appropriate conditions, however, Apistogramma bitaeniata is one of the most behaviorally rich dwarf cichlids available — the name sweglesi just happens to be how some of that history arrived in the hobby.
Conservation
Apistogramma sweglesi has no IUCN Red List assessment of its own — appropriately so, since it is not currently recognized as a distinct species and is generally treated as a synonym of Apistogramma bitaeniata. A direct check of the Red List returns no assessment under the name sweglesi, so it is recorded here as Not Evaluated (NE). The senior name, Apistogramma bitaeniata, was assessed as Least Concern (assessed 30 November 2020): it is widespread across the western Amazon, common in soft-water forest tributaries, and traded in volume as an ornamental without evidence of range-wide decline. There is no CITES listing. The conservation outlook for the fish behind the name is thus that of a broadly distributed, adaptable blackwater dwarf cichlid; the only thing genuinely 'at risk' about sweglesi is the name itself, which the prevailing taxonomy has already largely retired.