Taxonomy & naming
Teleocichla sp. "Tapajos II" is not a formally described species. It has no valid binomial, no describing author, no year of publication, and no entry in Eschmeyer's Catalog of Fishes, because no taxonomist has yet published a diagnosis of it. It is an informal taxon of the field and aquarium literature, written in the standard open-nomenclature convention for undescribed rapids cichlids: the genus name Teleocichla, the abbreviation "sp.", and a sequential collection code in quotation marks — here "Tapajos II", the numeral distinguishing it from the companion form "Tapajos I" gathered from the same river. The genus itself was erected by Sven O. Kullander in his 1988 Copeia monograph ("Teleocichla, a new genus of South American rheophilic cichlid fishes with six new species"), which named six dwarf, pike-like rheophiles from the rapids of the Tocantins, Tapajós, and Xingu and pointedly likened them to the African rapids cichlid Teleogramma — a case of convergence rather than kinship, since Teleocichla belongs with the Cichla–Crenicichla lineage of the Neotropics. Kullander (1990) already anticipated that the genus would swell well past those six as the rapids were worked further, and reviewers of the period (Stawikowski 1992, Buntbarsche Bulletin 153) noted at least four additional undescribed forms then known. Of the Tapajós members, two are described — Teleocichla prionogenys and Teleocichla proselytus — and "Tapajos II" is one of the river's still-unnamed rheophiles. The honest position is that this is a recognised but undiagnosed Teleocichla of the Tapajós, its placement in the genus inferred from body form, habitat, and provenance rather than from a published count; no author or date should be attached to it.
Morphology
Teleocichla are among the most peculiarly proportioned American cichlids — slim, almost cylindrical, faintly goby- or eel-like fishes shaped to wedge into rock crevices and ride out current rather than to cruise open water. Kullander (1988) coined the name to stress their parallel with the African rheophile Teleogramma brichardi, and the resemblance is purely functional: both are worm-like rapids specialists. Most members of the genus stay small, frequently under about 3.5 in standard length (Stawikowski recorded the largest of his undescribed Xingu forms at roughly 6 in), so "Tapajos II" is expected to be a modest fish in the range of a few centimetres up to perhaps 4 in. The body is tubular and the head somewhat flattened; the most telling adaptation, described by Rainer Stawikowski (Buntbarsche Bulletin 153, 1992), is the way these fish hold the rapids — they splay the pectoral fins flat into a horizontal plane like the wings of an aircraft, letting the rushing water press them down onto the rock instead of sweeping them away. Colour in the genus is cryptic: browns, greys, and olive tones broken by dark bars, mottling, or longitudinal stripes that blend the fish against stone and coarse sand, usually with fine speckling on head and fins. In the trade the Tapajós forms are separated chiefly by such pattern and colour detail. Sexual dimorphism is subtle and genus-typical — males tend to grow a little larger and may carry slightly extended unpaired-fin tips and stronger pattern in condition, females plainer. Being undescribed, the form has no published diagnostic counts to set it apart from its neighbours; it is recognised by provenance and pattern alone.
Habitat
This form is collected from the rapids of the Rio Tapajós, the major clearwater tributary entering the lower Amazon at Santarém, in the fast-water reaches around Itaituba and the São Luiz do Tapajós cataracts in Pará, Brazil. Teleocichla are obligate rheophiles, bound to the cataracts and channels where clear, warm, oxygen-charged water pours over and between boulders and coarse sand; they take station among the rocks, in crevices and beneath flat stones, and across the gravel pockets between them, and they avoid the still pools and the slack open channel entirely. Field chemistry for the genus comes mostly from the neighbouring Xingu, where Stawikowski (1992) measured the rapids at Altamira at about pH 6.5, very soft (around 1 °dH general hardness, less than 1 °dH carbonate hardness), roughly 120 µS conductivity, and a startling 90 °F during the September low-water season, with the fish over rocky bottom in about a metre of water. The Tapajós, also a bright clearwater river, presents comparable conditions: warm, soft, near-neutral water with strong current and high dissolved oxygen as the defining features. That habitat is the form's vulnerability as well as its home: the Tapajós rapids are squarely in the path of proposed hydroelectric development, most prominently the São Luiz do Tapajós scheme, which would drown the very fast-water stretches a rheophile like this depends on.
Feeding
Teleocichla are small benthic invertivores, and Kullander (1988) drew a sharp line between them and the ambush-feeding pike cichlids: where Crenicichla seize fish in a wide gape, Teleocichla have modest mouths suited to picking small prey off the substrate. They work the rocks and the gravel between them for aquatic insect larvae — chironomids, mayfly and blackfly larvae, the abundant interstitial fauna of fast water — together with other small invertebrates and the organic matter and biofilm bound to the stones. The slim, bottom-hugging build and the crevice-working habit are all of a piece with a fish that grazes surfaces rather than chases prey through open water. "Tapajos II" is expected to follow this genus-typical pattern as a micro-invertivore of the rapids biofilm and interstitial gravel. Nothing about its anatomy suggests piscivory; it is a small, specialised crevice forager, not a predator of other fishes.
Mating
Reproductive behaviour in wild Teleocichla is sparsely documented because the rapids are so hard to observe, but the broad pattern is understood: these are pair-forming, cave- or crevice-spawning substrate brooders, not mouthbrooders. Stawikowski (1992) reported that adult males in the Xingu rapids hold and defend small territories centred on individual stones, pits, or holes in the rock, retreating beneath flat slabs when threatened, and that the genus varies markedly in how sociable or pugnacious different species are — in one striking observation he found three different Teleocichla species sheltering under a single rock, sympatric and syntopic, kept reproductively apart by behaviour rather than by space. In aquaria, related Teleocichla pair off and court at close range within and around a chosen cavity that stands in for the natural rock shelter, the female taking the leading role at the spawning site. "Tapajos II" is expected to share this crevice-oriented, pair-forming behaviour; the particulars of its territory size and courtship sequence have not been described for this form.
Breeding
By analogy with its described congeners, Teleocichla sp. "Tapajos II" is understood to be a cave/crevice-spawning substrate brooder. The genus was first bred not by American aquarists — who found the fish nearly impossible to import alive, since it ships poorly and dies quickly out of moving water — but by German keepers, with Schliewen and Stawikowski (1989, DATZ) among the earliest to record Teleocichla spawnings. The documented pattern has eggs laid on the wall or roof of a cave or crevice and guarded there, the female taking the primary share of egg- and larva-tending while the male holds the immediate surroundings. Clutch sizes in these dwarf cichlids are modest, on the order of a few dozen up to perhaps a hundred-plus eggs in keeping with the small body, though no precise count is published for this form. The wrigglers are kept within the shelter and guarded until free-swimming, parental care extending through the early fry stage. (Specific wild breeding data for "Tapajos II" are not on record; the account here is genus-typical and flagged as such.)
In the aquarium
Teleocichla are specialist fishes for the experienced rheophile keeper, and the undescribed Tapajós forms reach the hobby only sporadically as wild imports — historically a real gamble, since the fish are difficult to catch and notoriously poor shippers that do not survive transport in still water. They are emphatically not community fish; they need a tank built to reproduce the rapids.
The single most important parameter is flow. Provide strong, well-oxygenated current from powerheads or a river-tank manifold over a bed of rounded gravel and coarse sand, with smooth boulders and water-worn stones arranged into crevices and caves so that every fish has its own bolt-hole — Stawikowski's wild fish each guarded a stone or hole and bolted under flat rock when alarmed, and captive layout should respect that. Keep the water warm (around 81–90 °F; the wild rapids run remarkably hot at low water), soft, and near-neutral (pH roughly 6.0–7.0), and above all clean and oxygen-rich. Rapids fish tolerate stagnation and dissolved waste poorly, so heavy turnover, vigorous biological filtration, and disciplined maintenance are non-negotiable rather than optional. A tight cover suits these restless, current-oriented fish.
Feed small meaty foods appropriate to a benthic invertivore — frozen and live bloodworm, daphnia, and brine shrimp, plus small sinking prepared foods — delivered so they reach the bottom where the fish forages; surface flake is largely wasted on a crevice-grazer. Conspecific tolerance is unpredictable: some Teleocichla are reasonably social and others sharply territorial, so either keep a single pair or give a group generous rockwork and floor space so subordinates can escape. Suitable tankmates are other rheophilic, current-tolerant Amazonian fishes of compatible temperament; avoid slow-water community species and anything that will outcompete a small bottom specialist at feeding. The recurring ways keepers lose these fish are too little flow and oxygenation, too few rock shelters, and any lapse in water quality.
Conservation
Teleocichla sp. "Tapajos II" has not been evaluated by the IUCN, and as an undescribed form without a valid scientific name it has no Red List assessment of any kind — no status, no category, no published criteria. That formal silence should not be read as reassurance. As an obligate rheophile of the Tapajós rapids it occupies precisely the habitat most exposed to hydroelectric development on the river, above all the São Luiz do Tapajós scheme, which would flood and slacken the fast-water stretches that current-dependent specialists cannot do without — the same threat that hangs over the rapids endemics of the dammed Xingu. Narrow-range rheophilic cichlids of the Amazonian shield rivers are widely flagged as among the fauna most vulnerable to such projects. The conservative reading is that this habitat-restricted form is potentially imperilled by flow alteration even though it is formally unassessed. No conservation status should ever be invented for it; the honest statement is that it is unassessed, rapids-restricted, and exposed to dam-driven habitat loss.