Taxonomy & naming
Spatuloricaria puganensis was originally described as Loricaria puganensis by Noel Pearson in 1937 in the Proceedings of the California Academy of Sciences (Series 4, volume 23, number 7, p. 96), from type specimens collected at Pusoc on the Río Marañon, Peru. The Catalog of Fishes (Eschmeyer, CAS) recognises the valid combination Spatuloricaria puganensis, with Loricaria puganensis as the junior synonym.
The genus Spatuloricaria Rojas-Mora & Fichberg, 2004 — formally elevated from a subgenus — groups the flattened, spatula-headed whiptail catfishes within the subfamily Loricariinae. The combination of a dramatically flattened head profile (spatulate when viewed from above), an elongated caudal filament, and the characteristic loricariid body armour defines the genus. Armbruster (2004) placed Spatuloricaria within Loricariini, close to the genera Loricaria and Rineloricaria.
S. puganensis has no assigned L-number or LDA-number in the DATZ/Das Aquarium numbering systems; the species appears in the trade sporadically as a by-catch of ornamental collections in Peru and has never been systematically coded. Ferraris (2003) treated it in the comprehensive checklist of the freshwater fishes of South and Central America.
Morphology
Adults reach approximately 8.5 in standard length (SL), making S. puganensis one of the larger whiptail species encountered in the hobby. The body is strongly dorsoventrally flattened — almost ray-like in cross-section — covered in keeled bony scutes that form a continuous coat of armour from the snout to the base of the tail. A pair of elongated filaments extends from the upper and lower lobes of the caudal fin, and in large adults these filaments can extend several centimetres beyond the fin edge, giving the fish its striking silhouette.
Ground colour is a warm sandy to brownish grey, variously marked with darker reticulations or faint spotting that provides camouflage against gravel and stone substrates. The ventral surface is pale, sometimes whitish. The snout is broad and spatulate — the defining feature of the genus — with the eyes positioned laterally and relatively high on the head. The mouth is ventrally placed and equipped with small bicuspid teeth suitable for scraping biofilm and periphyton from hard surfaces.
Sexual dimorphism is modest but consistent. Adult males develop more prominent odontodes on the cheeks and along the pectoral fin spines, which are also typically thicker and slightly shorter than those of females. Viewed from above, the male's head is shaped more like an isosceles triangle, while the female's head approaches an equilateral triangle. Gravid females are noticeably broader across the body when seen from above.
Habitat
Spatuloricaria puganensis is native to the Marañon River basin in northern and central Peru, with additional records from the Chotano tributary (Cajamarca region) and from the Madre de Dios basin further south. The Marañon drains the eastern Andes and is a major tributary of the upper Amazon; its fast-flowing foothill reaches carry cold, clear to moderately turbid, well-oxygenated water over predominantly sand, gravel, and bedrock substrates.
Field photographs document individuals from the Río Chotano (ca. 8 in TL), collected over gravel and sand in shallow, current-exposed riffle zones. The fish presses its flattened body flush with the bottom, using its robust pectoral and pelvic fins to maintain position against the current — a posture that makes it nearly invisible against matching substrate. Water temperatures in Andean foothills rivers at the elevations where S. puganensis occurs typically range from around 72 °F to 81 °F; pH is generally neutral to slightly acidic and hardness is low.
The species is associated with substrates that support periphyton and algal biofilm growth — fine sand and gravel beds in moderate to strong current, sometimes partially shaded by riparian vegetation or overhanging rocks. Soft-bottomed, slow-water habitats are not typical for this genus.
Feeding
Spatuloricaria puganensis is primarily an aufwuchs and biofilm grazer, using its small bicuspid teeth and powerful sucker-mouth to rasp diatoms, green algae, detritus, and microbial films from the surfaces of sand grains, gravel, and submerged rocks. Gut content analysis of related Spatuloricaria species confirms a dominant algal and fine organic matter diet. Like most Loricariinae, it supplements grazing with fine particulate organic matter ingested as it sifts sandy substrate.
In the aquarium, the diet should reflect this grazing lifestyle. Sinking algae wafers, spirulina tablets, and blanched vegetables (courgette/zucchini, cucumber, blanched peas, spinach) should form the backbone of the feeding programme. The fish will also pick over a sandy substrate and clean smooth rocks of algae. Live or frozen invertebrate foods — bloodworm, daphnia — can be offered occasionally and are accepted, but the diet should remain predominantly plant-based and the fish should not be overfed with protein-rich foods.
A sandy substrate is important not only for feeding behaviour but for the fish's physical wellbeing; it spends much of its time in contact with the bottom and can abrade its ventral surface on coarse substrates.
Mating
The reproductive biology of Spatuloricaria puganensis has not been formally documented in the scientific literature, and there are no published captive breeding reports on PlanetCatfish or in the specialist hobby press as of 2026. What is known comes from observations of closely related loricariin whiptails (Rineloricaria spp., Loricaria spp.) and limited keeper observations.
Males are presumed to become territorial around sheltered cavities or narrow interstices under rocks and woody debris during the breeding season, paralleling the behaviour of other Loricariinae cave-spawners. The pronounced odontodal development on the cheeks and pectoral spines of breeding males — a common feature in the subfamily — suggests that male–male competition for spawning sites is significant. Females approach mature size later than males and, when gravid, show the characteristically wider body that allows visual sexing from above.
In the wild, breeding in Andean foothill rivers is likely correlated with seasonal water temperature and flow fluctuations — the receding dry season concentrating fish around suitable microhabitats.
Breeding
No captive breeding of Spatuloricaria puganensis has been formally reported, and the species is uncommon enough in the hobby that reproductive data remain sparse. The genus belongs to Loricariinae, virtually all of whose members are cave or crevice spawners with paternal brood care — males guard eggs deposited in a sheltered cavity, fanning them with pectoral and pelvic fins to maintain oxygenation.
By analogy with well-documented congeners and relatives (Rineloricaria lanceolata, Loricaria simillima), eggs are expected to be adhesive, deposited on the interior surfaces of the spawning cavity, and guarded by the male until the yolk-sac fry are free-swimming. Clutch sizes in similarly proportioned loricariin species typically number in the dozens to low hundreds. The elongated caudal filaments of adult males in some whiptail species are thought to play a role in stimulating females during courtship, though this is not confirmed for S. puganensis specifically.
Any aquarist wishing to attempt breeding should provide a long tank (at least 47 in) with strong, well-oxygenated flow, sandy substrate, smooth flat stones or narrow ceramic caves, and gradual temperature cycling to mimic seasonal cues.
In the aquarium
Spatuloricaria puganensis is an infrequently available species suited to experienced keepers rather than beginners. Its adult size of around 8.5 in SL — and total length closer to 10–11 in once the caudal filaments are factored in — demands a tank of at least 47 in in length; 59 in is more appropriate for a single adult, and larger still for a pair or small group. Whiptails of this genus are not particularly active swimmers but do patrol territory and will claim a stretch of bottom, so floor area matters more than height.
Water quality must be excellent: strong filtration producing good flow, stable oxygenation, and regular partial water changes are essential. Parameters should reflect the Andean foothill origin: temperature 72–81 °F, pH 6.5–7.5, low to moderate hardness. The fish is sensitive to poor water quality and stagnant conditions; ammonia and nitrite must be undetectable.
A sandy substrate of at least 2 in depth is strongly recommended, as the fish will sift and shuffle through it. Flat stones for resting and grazing, a few pieces of driftwood, and some planted cover complete an appropriate setup. The species is generally peaceful toward other fish and does not bother tankmates too large to be viewed as food. Keep singly or in male–female pairs unless a very large tank is available; intraspecific competition among males for territory can become a source of stress. Compatible tankmates include mid-water tetras, peaceful cichlids, and Corydoras.
Conservation
The IUCN Red List assessed Spatuloricaria puganensis as Least Concern in 2014, noting a wide distribution across the Marañon basin and no evidence of major threats. The species is not heavily targeted by the ornamental fish trade and is not listed under CITES. No captive-breeding programme exists for this species in the hobby, and specimens entering the trade are wild-caught.
The upper Amazon and its Andean tributaries face increasing pressure from hydroelectric development, agricultural expansion, and sediment run-off from deforestation in the Peruvian highlands. These pressures can reduce the quality of the clear, fast-flowing, gravel-bottomed microhabitats on which whiptails depend. Siltation in particular — by smothering biofilm communities on rocks and gravel — can remove the food base for algae-grazing loricariids. The IUCN assessment notes that an update would be desirable; no reassessment has been published as of 2026.