Taxonomy & naming
Crenicichla tingui was described by Sven O. Kullander and Carlos A. Santos de Lucena in 2006, in their revision of the pike cichlids of the Atlantic coastal rivers of southeastern Brazil published in Neotropical Ichthyology (volume 4, issue 2, pages 127–146). That paper recognized six Crenicichla from the region — three of them, including tingui, new to science — and the holotype of Crenicichla tingui is a 4 in female (MCP 12606) collected on 7 February 1988 from the rio Jacarei, on the municipal border of Paranaguá and Morretes in Paraná, just below the bridge at km 18 of the BR-277 highway. Ten paratypes from the rio Itapocu, rio Cubatão and rio Cachoeira drainages, some catalogued as far back as 1909 and 1913, round out the type series. The species sits in the Crenicichla lacustris group (sometimes treated as a subgenus, Lacustria), a cluster of temperate-to-subtropical pike cichlids of southern and southeastern Brazil that also contains Crenicichla lacustris, Crenicichla iguapina, Crenicichla maculata, Crenicichla punctata and the inland Crenicichla iguassuensis. Its closest look-alikes are Crenicichla lacustris and Crenicichla iguassuensis, from both of which it is separated on colour pattern. In 2023 a comprehensive phylogenetic revision of the pike cichlids by Varella, Kullander and colleagues reorganized the old catch-all genus Crenicichla, splitting off several lineages into new genera (Saxatilia, Lugubria, Wallaciia, Hemeraia); the lacustris group, however, was retained within Crenicichla — formalized as the subgenus Lacustria — so Crenicichla tingui keeps its original genus name. The epithet has no junior synonyms.
Morphology
Crenicichla tingui is an elongate, cylindrical pike cichlid of modest size for the genus. FishBase lists a maximum of 7.5 in standard length, but the type series tells a more nuanced story: the largest male measured was 5 in and the largest typical female about 4 in, with one exceptional paratype female of 7.5 in — so most individuals are in the 4–5 in range and large specimens are uncommon. The body depth is 17.6–20.8% of standard length, the snout long and pointed in profile, and the lower jaw is slightly prognathous, the classic pike-cichlid muzzle built for seizing prey. The mouth is large with rows of small, pointed, slightly recurved teeth, the outer row movable and the inner rows depressible. The dorsal fin carries 21–22 spines and 12–14 soft rays and the anal fin 8–10 soft rays; the soft dorsal is pointed and in both sexes the middle rays may be drawn out toward the caudal base. The defining feature is the colour pattern: a dark lateral band runs unbroken from the eye to the base of the tail, the suborbital (cheek) stripe is short and narrow — sometimes reduced to a small spot at the eye's margin — and, critically, there are no dark spots on the side of the head. The flanks carry rows of dark spots, and unusually for the group both the band and the spotting are about equally well expressed in the two sexes; in Crenicichla lacustris, by contrast, the band tends to fade behind a spot pattern in males. Sexual dimorphism is therefore subtle: males simply tend to carry more numerous, more sharply defined spots on the unpaired fins and on the body, while females show fewer and slightly lighter spots at a given size. The absence of fine vertical stripes separates tingui from most of its relatives except Crenicichla iguassuensis, which it then distinguishes from by its continuous band and short suborbital stripe.
Habitat
Crenicichla tingui is a narrow-range endemic of the Atlantic-slope coastal drainages of southern Brazil. The original description records it from the rio Itapocu drainage and from a set of small rivers draining into two large coastal bays: the baía da Babitonga (via the rio Cubatão system) and the baía de Paranaguá (via the rio Jacarei and rio Cachoeira drainages). These waters span the boundary between northern Santa Catarina and coastal Paraná, all within the Southeastern Mata Atlântica freshwater ecoregion — a band of short, fast rivers that drain the seaward face of the Serra do Mar to the Atlantic, separated from the inland Paraná basin by the mountain divide. These are typically clear, well-oxygenated, rocky-bottomed streams and small rivers running through (or through what remains of) Atlantic rainforest, with the species reported around the rio Cubatão among other localities. As a subtropical coastal-river fish rather than a lowland Amazonian one, Crenicichla tingui experiences cooler and more seasonal conditions than its tropical congeners: water in this ecoregion is generally soft and circumneutral, with temperatures broadly in the high-teens to high-twenties Celsius and pH near neutral. No detailed in-situ chemistry was published with the type material, and FishBase carries no measured depth range; pike cichlids of this kind are creatures of the shallow, structured margins — among rocks, roots and submerged wood — rather than open or deep water.
Feeding
Like the rest of its genus, Crenicichla tingui is a predator. FishBase records the species as feeding on fish, and stomach analyses of related coastal Crenicichla in the same revision confirmed fish remains as the staple. The body plan tells the same story: the elongate, low-slung form, large protrusible mouth, pointed snout and recurved teeth are the toolkit of a lurking ambush hunter that lies among rocks and submerged structure and lunges at small fish and invertebrates that stray within reach. FishBase places its trophic level near 3.3, typical of a small-to-medium piscivore that also takes aquatic insects and crustaceans, especially when young. In its coastal-river community it occupies the role of a mid-level stream predator, hunting from cover in the structured shallows rather than chasing prey in open water.
Mating
No field study has documented the courtship of Crenicichla tingui specifically, so what can be said is drawn from the consistent reproductive biology of the genus and especially of its temperate lacustris-group relatives. Pike cichlids form monogamous pairs and become strongly territorial as spawning approaches, the pair jointly defending a patch of bottom centred on a sheltered spawning site. Courtship in Crenicichla involves mutual displays, lateral presentation and jaw-to-jaw sparring, with the larger male and the often plumper, more brightly coloured female settling into a bonded pair before spawning. In the lacustris group the sexes are only modestly dimorphic — in Crenicichla tingui males simply carry bolder fin and body spotting — so pairing depends less on dramatic colour difference than on size and behaviour. As in other pike cichlids, the female typically takes the leading role at the nest while the male patrols and defends the wider territory.
Breeding
Crenicichla tingui has not been bred or its spawning observed in any published account, but its mode can be stated with confidence from the genus: pike cichlids are biparental substrate- and cave-spawners. The pair selects and cleans a sheltered surface — the roof or wall of a rock crevice, an undercut, or a cavity among roots and wood — and the female lays a clutch of adhesive eggs that both parents then guard intensively. The female tends and fans the eggs while the male defends the perimeter; after the eggs hatch, the wrigglers are moved to pits and the free-swimming fry are shepherded as a school and shielded from predators by both parents for an extended period. Clutch sizes are undocumented for this species; lacustris-group congeners of comparable size typically lay on the order of a few hundred eggs per spawning (genus-typical figure), with the larger pike cichlids capable of more. The cooler, seasonal regime of its Atlantic-coastal rivers suggests reproduction is likely keyed to the warmer, wetter part of the year, though this has not been confirmed in the wild.
In the aquarium
Crenicichla tingui is essentially absent from the aquarium hobby. As a small-range endemic of protected Atlantic Forest coastal rivers it is rarely collected and effectively never traded, so there is no established body of keeping or breeding experience for the species — anyone encountering it in captivity would be extrapolating from better-known lacustris-group pike cichlids. On that basis, sensible expectations follow from its biology. It is a medium-sized, elongate predator that would need a long tank with a generous footprint rather than a tall one — on the order of 47 in or more for a single fish or a pair — aquascaped with abundant rockwork, caves, driftwood and shaded retreats to provide territory and spawning sites. Because it comes from cool, clear, well-oxygenated subtropical streams rather than warm tropical lowlands, it would want a lower, more seasonal temperature than most aquarium cichlids (roughly 64–79 °F), soft to moderately hard water near neutral pH, strong filtration, brisk flow and high oxygen. It is a confirmed fish-eater, so tankmates small enough to swallow would be at risk, and like most pike cichlids it can be intolerant of conspecifics and similar species outside of a bonded pair; a divided, heavily structured tank that lets a subordinate fish escape is the prudent approach to pairing. None of this is tested husbandry for tingui itself — it is the honest read of an untraded wild predator, not a hobby track record.
Conservation
The IUCN Red List assesses Crenicichla tingui as Least Concern, in an assessment carried out on 7 November 2018 by Brazil's Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) and published in 2022. The assessment notes that the species is naturally uncommon but identifies no significant threats to its population, and it carries no CITES listing. That said, Least Concern should be read against the species' narrow range. Crenicichla tingui is restricted to a handful of short coastal drainages in Paraná and Santa Catarina, all within the Atlantic Forest (Mata Atlântica) — one of the most heavily cleared and densely populated biomes in Brazil. The coastal rivers it depends on are exposed to deforestation, urban and industrial expansion around the bays of Babitonga and Paranaguá, dams and water abstraction, pollution and sedimentation, and the spread of non-native fishes. None of these is presently documented as driving the species toward decline, but a habitat-limited endemic of a fragmented, fast-developing coastal landscape warrants closer monitoring than its broad-brush Least Concern label might suggest.