Taxonomy & naming
Chaetostoma changae was described by Nathalie J. Salcedo in 2006 in Copeia (volume 2006, number 1, pages 60–67), from type specimens collected near Tingo María, a backwater near Puerto Nuevo flowing into the Río Tullamaya, at approximately 9°18'S, 75°59'W, Departamento Huánuco, Peru. The Catalog of Fishes (Eschmeyer, CAS) recognises Chaetostoma changae Salcedo, 2006 as a valid species with no junior synonyms.
The species was assigned to the L-number system as L334, and the hobbyist common name 'Broken Rubbernose' refers to the pattern of the diagnostic banded dorsal fin, which creates a broken or interrupted visual impression relative to the uniformly pigmented body.
The genus Chaetostoma (Tschudi, 1846) is placed in the tribe Chaetostomini within subfamily Hypostominae. It currently contains around 50 valid species and represents the dominant loricariid lineage of Andean foothill and montane rivers from Colombia south to Bolivia. The Huallaga River basin of central Peru is the most species-diverse area within the genus, with seven species currently recognised from that drainage alone, of which C. changae is one. Molecular phylogenetic work (Ballen et al. 2016 and subsequent studies) confirms the close affinity of C. changae with other Huallaga endemics and its more distant relationship to coastal and Colombian Chaetostoma lineages.
Morphology
Adults reach a maximum of 3 in standard length (SL) — small even by Chaetostoma standards. The body is stocky and strongly flattened ventrally, with a broad, rounded head bearing the characteristic rubbery-textured, naked (unplated) snout that gives the 'rubbernose' group its vernacular name. The abdomen is also unplated, distinguishing Chaetostoma from genera such as Ancistrus, which bear abdominal plates.
The diagnostic features separating C. changae from its congeners, as established by Salcedo (2006), include: a conspicuously banded dorsal fin (versus uniformly pigmented in most Huallaga congeners); the presence of a fleshy excrescence on the posterior tip of the supraoccipital (an unusual derived character within the genus); typically 9 branched dorsal-fin rays (rarely 8 or 10); seven infraorbital plates (versus six in most sympatric congeners); and evertible cheek plates bearing 2–4 hypertrophied, hooked odontodes. The irregularly shaped papillae on the naked snout and the absence of odontodes on the first anal-fin ray further distinguish it from closely related species.
Coloration is described as uniform or marbled — consistent dark brown to olive pigmentation without the strong spotting or banding on the body itself that characterises species such as C. lineopunctatum. Sexual dimorphism includes a broader, heavier head in males and proportionally larger, broader pelvic fins, which are thought to assist in sperm placement over egg clutches in fast-flowing water.
Habitat
Chaetostoma changae is known only from the upper Huallaga River drainage near Tingo María, Departamento Huánuco, Peru, at approximately 2133 ft above sea level. This is the Andean piedmont zone — rivers here descend from the eastern Andes, transitioning from clear, fast-flowing montane streams to the turbid, lower-gradient waters of the Amazonian lowlands. The type locality is a backwater connected to the Río Tullamaya, a direct Huallaga tributary.
The broader Chaetostoma ecology in this region is characterised by fast-flowing, clear streams and rivers with rocky and cobbled substrates, where species occupy the hyporheic zone under and between boulders and large cobbles. Water temperatures in Huallaga headwaters in the Tingo María vicinity are typically in the range 68–79 °F, pH near neutral to slightly acidic (6.5–7.2), and dissolved oxygen is high due to aeration from turbulence. The species is demersal and rheophilic — adapted to life in current.
The IUCN Red List assessment (Ortega et al. 2016) notes that the species occurs within a very restricted area of occupancy, making its specific habitat conditions critical to its survival. Deforestation of the Huallaga valley for coca cultivation and subsequent conversion to agriculture has heavily impacted streamside vegetation and altered hydrology across much of the range.
Feeding
Chaetostoma species are periphyton and aufwuchs grazers, using the ventral suction disc and fine teeth to rasp algae, diatoms, and organic detritus from rock surfaces in fast-moving water. The rubbery, cartilaginous snout tissue is an adaptation that allows the fish to press firmly against irregular rock surfaces while maintaining the suction seal needed to resist dislodgement by current.
In the wild, gut content analyses of related Chaetostoma species consistently show a dominance of diatoms, filamentous green algae, and fine detrital material, with some incidental ingestion of invertebrate fragments. No evidence of significant xylophagous (wood-eating) behaviour has been documented in the genus.
In the aquarium, sinking algae wafers and spirulina-based discs form the appropriate dietary staple. Blanched zucchini (courgette), cucumber, and spinach are accepted. Small live or frozen invertebrate foods — bloodworm, Cyclops, Artemia — can be offered as supplements. Adequate algal grazing surface within the tank (smooth rock surfaces and glass panels) reduces competition for sinking prepared foods. As a predominantly herbivorous grazer, the species does not require and should not receive a high-protein carnivore diet.
Mating
No specific courtship observations for C. changae appear in the primary literature, but the reproductive behaviour of the genus is known from aquarium observations of other Chaetostoma species. Males are territorial and defend prime breeding sites — usually the underside of a flat, overhanging rock or a large smooth cobble in a well-oxygenated area of the tank.
Males in breeding condition show the sexually dimorphic traits noted above: the broader, heavier head and the proportionally enlarged pelvic fins are particularly conspicuous. The pelvic fins of males in the genus are thought to be functionally significant in fertilisation, as the male presumably positions them over the egg clutch to reduce sperm dispersal by current — a remarkable adaptation for a fast-water spawner. Conditioning adults on a varied diet with regular water changes and the provision of appropriate flat stone spawning surfaces is recommended to encourage courtship behaviour.
Breeding
The breeding mode in Chaetostoma is open-substrate spawning in fast-flowing water, with the eggs adhering to the underside of a flat rock or cobble surface. The male remains upside-down beneath the clutch, covering the eggs with his body and guarding them against predation. This unusual posture — the male inverted against the ceiling of the spawning site — has been documented in several Chaetostoma species and appears to be characteristic of the genus. The enlarged pelvic fins are thought to form a barrier reducing current-induced sperm loss during fertilisation.
No breeding reports for C. changae specifically are recorded on PlanetCatfish as of 2025, and captive reproduction of this Endangered species remains unconfirmed in the literature. The closely related and more commonly kept C. thomsoni and C. milesi provide the best analogues for the likely breeding requirements: well-oxygenated water with significant flow, flat smooth rock surfaces positioned at angles replicating natural streambed conditions, pH 6.5–7.2, temperature 72–77 °F, and varied conditioning foods. Clutch size in the genus is typically in the range of 20–80 relatively large eggs, and incubation takes approximately 5–7 days at typical temperatures.
In the aquarium
Chaetostoma changae is a specialist aquarium fish — rarely offered in trade and most likely appearing through specialist importers bringing Peruvian fish, or through collectors who deliberately target upper Huallaga material. Its L-number designation (L334) assists hobbyists in recognising and documenting it. Given the IUCN Endangered status, responsible keeping means documenting holdings and pursuing captive breeding rather than treating the species as a short-term acquisition.
The fundamental husbandry requirement is clean, fast-flowing, well-oxygenated water: a powerhead or spray bar delivering vigorous surface agitation and significant current in at least part of the tank is essential. Temperature should be maintained at 72–79 °F, pH 6.5–7.2, and hardness kept low to moderate. The substrate can be smooth cobble and fine sand; smooth flat rocks positioned horizontally and vertically provide both hiding places and potential spawning surfaces.
A tank of 20 US gal or more is appropriate for a pair; the species is peaceful toward non-competitive tankmates (small South American characins, Corydoras) but may be territorial toward other Chaetostoma or suckermouth catfishes sharing limited rock territory. Sinking algae wafers should be provided daily; supplementary blanched vegetables and occasional invertebrate foods round out the diet. The species is sensitive to elevated nitrate, poor oxygenation, and high organic load — thorough filtration and regular partial water changes are non-negotiable.
Conservation
Chaetostoma changae is assessed as Endangered (EN; criterion B1ab(iii,v)) on the IUCN Red List, with the most recent published assessment made in April 2014 by Ortega and colleagues. The Endangered designation reflects an estimated extent of occurrence below 5,0 mi², a single location with continuing habitat decline in area and quality (iii), and a continuing decrease in the number of mature individuals (v).
The Huallaga valley near Tingo María has been extensively deforested and converted to agriculture, much of it associated historically with coca cultivation. Sedimentation, agrochemical runoff, and altered streamflow from riparian deforestation all degrade the clear, fast-flowing rocky-bottom microhabitat on which this species depends. The city of Tingo María itself exerts direct pressure through urban effluent on the river and its tributaries.
No captive breeding programme for C. changae is known to be in operation. The species is not listed under CITES. Given the narrow range, the confirmed ongoing habitat decline, and the absence of ex-situ conservation activity, this is a genuinely at-risk loricariid whose population trajectory without habitat protection is concerning. Aquarists who obtain specimens have a meaningful role to play in documenting the species and attempting captive propagation.