Taxonomy & naming
Peckoltia greedoi was described by Jonathan W. Armbruster, David C. Werneke, and Milton Tan in their 2015 paper 'Three new species of saddled loricariid catfishes, and a review of Hemiancistrus, Peckoltia, and allied genera (Siluriformes)', published in ZooKeys 480:107 (doi: 10.3897/zookeys.480.6540). The holotype is MCP 21972, 3 in SL, collected on 23 July 1998 by R. Reis, J. P. Silva, E. Pereira, and J. Montoya from the Río Gurupi at highway BR 316, at the border of Pará and Maranhão states, Brazil (−1.8003°, −46.3167°).
The Catalog of Fishes (Eschmeyer, CAS) recognises the valid combination Peckoltia greedoi without synonyms. The species was previously misidentified: Armbruster (2008) had reported Peckoltia vittata from the Gurupi drainage, but that record is now reassigned to P. greedoi (Armbruster et al., 2015).
Phylogenetic placement follows Lujan et al. (2015), whose molecular analysis showed that several 'Hemiancistrus' species and newly described forms belong within Peckoltia sensu novo. P. greedoi is placed in Peckoltia — tribe Ancistrini, subfamily Hypostominae (Armbruster, 2004) — based on having the dentaries meeting at an angle greater than 90° and lacking the synapomorphies of other Ancistrini genera. No L-number has been assigned to this species.
Morphology
Adults reach a maximum of 3 in SL in the type series (largest specimen examined; Armbruster et al., 2015). The body is moderately elongate, broadest at the pectoral fin insertions and tapering to a triangular caudal peduncle. The head and nape form a continuous arc from snout tip to the insertion of the dorsal fin; the snout is rounded in lateral profile.
The diagnostic coloration consists of a red-brown base colour on the flanks with three dark dorsal saddles: the first below the mid-dorsal fin, the second spanning the posterior end of the dorsal fin, and the third from the preadipose plate to approximately mid-adipose membrane. The saddles connect at the median plate series and appear to be composed of two fused bars each. The head is uniformly dark brown — a key character distinguishing P. greedoi from most other Peckoltia, which carry spots, mottling, or streaks on the head. The dorsal fin carries oblique spots forming faint bands; the caudal fin has three to four transverse bands.
The eyes are large relative to head length (orbit diameter approximately 22.9% of head length), sited high on the head with the dorsal orbital rim forming a tall crest — the feature that prompted the Greedo comparison. The iris operculum is present. The abdomen is largely naked posterior to the pectoral girdle, with platelets confined to specific zones around the girdles. Cheek odontodes are evertible, with 17–40 present (mode 33); the longest extends to approximately the level of the posterior edge of the pectoral spine. Dentary tooth count 16–39 (mode 28); premaxillary tooth count 20–38 (mode 27).
Habitat
Peckoltia greedoi is known only from the type locality: the Río Gurupi at highway BR 316, on the state border between Pará and Maranhão in eastern Brazil. The Gurupi drains eastward into the Atlantic and is classified within the Maranhão coastal drainages ecoregion — a distinct biogeographic unit separate from the Amazon proper. The type collection was made on 23 July 1998 during the dry season, when the river at this point would be at lower flow, exposing more rocky substrate.
No detailed field notes on water chemistry at this locality are published in the original description, but the Gurupi at its upper–mid reaches is characterised by clear-to-dark, low-conductivity water typical of eastern Brazilian shield drainages: generally soft, slightly acidic, and warm, with temperatures consistent with the regional tropical climate (approximately 77–84 °F). Rocky substrate with moderate to strong current is the expected microhabitat for a Peckoltia in this region, consistent with the genus's broader ecology.
The species appears to have a very restricted natural range — all known specimens come from a single locality — though the true range may extend along the Gurupi drainage beyond the collection point.
Feeding
No gut-content data specific to Peckoltia greedoi have been published. The species' dietary ecology must be inferred from morphology, genus-level data, and comparison with ecologically similar Peckoltia.
The mouth of P. greedoi is small, slightly ovoid, and surrounded by papillose lips — morphologically consistent with a grazer on fine biofilm and aufwuchs rather than a hard algae scraper. Tooth cusp proportions (bicuspid teeth with lateral cusp one-half to three-quarters the length of the medial cusp) are typical of Peckoltia and suggest versatile scraping of organic material from rocky and woody surfaces. The largely naked abdomen posterior to the pectoral girdle is consistent with rock-sitting behaviour — the fish presses its bare abdomen against substrate as it grazes.
In captivity, Peckoltia species generally accept a wide diet: high-quality sinking pellets, spirulina wafers, blanched vegetables (courgette, cucumber, spinach), and periodic offerings of frozen or live foods (bloodworm, brine shrimp). PlanetCatfish notes the species can be kept with small shrimp and appears to be relatively peaceful across a wide range of tankmate sizes. Given the scarcity of the species in captivity, direct aquarist accounts are limited.
Mating
No captive observations of courtship in Peckoltia greedoi have been published. Given the absence of any breeding report on PlanetCatfish, inferences must be drawn from genus-level behaviour, which is reasonably well documented in related species such as P. compta and P. vittata.
Peckoltia species are cave-spawning loricariids with paternal brood care, following the ancestral Ancistrini reproductive mode. Males are expected to establish and defend crevice or cave territories, displaying evertible cheek odontodes and hypertrophied pectoral-spine odontodes during male–male competition. Females in breeding condition develop a noticeably broader abdominal profile; the pectoral region visible from above gives the most reliable visual cue.
Conditioned aquarists keeping this species would logically follow the same protocols used for related cave-spawning Peckoltia: provide multiple tight-fitting caves of appropriate diameter, feed a varied high-quality diet, and use water change-induced parameter shifts (slight temperature drop followed by warming, softer water) as spawning triggers. The species' docile nature across size classes — as noted by PlanetCatfish — suggests it may be compatible with a range of tankmates even during breeding attempts.
Breeding
No successful captive breeding of Peckoltia greedoi has been reported in the available literature or on PlanetCatfish as of the time of this writing. The species is extremely rarely imported — only one spot record exists on PlanetCatfish, and no registered keepers or breeding reports are recorded — making captive breeding data essentially non-existent.
Based on its genus placement and morphology, P. greedoi is expected to be a paternal cave spawner in the Ancistrini tradition: adhesive eggs deposited on the interior walls of a tight crevice, guarded and fanned by the male until fry are free-swimming. Clutch sizes in comparable small-to-medium Peckoltia typically range from 10 to 40 eggs. Incubation would be expected to take 5–8 days at tropical temperatures.
The Gurupi drainage origin — an Atlantic-draining eastern Brazilian river — suggests water chemistry preferences distinct from Amazonian relatives: likely soft, slightly acidic, warm water (pH 5.5–7.0, temperature 75–82 °F). Any serious attempt at captive breeding would benefit from replicating this water chemistry rather than using standard Amazonian soft-water conditions.
In the aquarium
Peckoltia greedoi is a genuine rarity in the hobby. No L-number was assigned, and the species has almost never been deliberately imported for the trade. PlanetCatfish records no registered keepers and no sighting records, confirming that virtually all aquarist knowledge of the species derives from the original scientific description rather than direct husbandry experience.
Were it to become available, its size (under 3 in SL) and reportedly peaceful disposition would make it well suited to a mid-sized community aquarium of 20 US gal or larger. PlanetCatfish notes it can be combined with a very wide array of tankmates — from small shrimp to moderately large cichlids — which, if accurate for the species, would mark it out as unusually tolerant among Peckoltia. A setup of rock piles and wood tangles replicating the rocky substrate of the Gurupi river would be appropriate; plants are not vital.
Water parameters should reflect its eastern Brazilian provenance: soft, slightly acidic to neutral water (pH 5.5–7.0), warm temperatures (75–82 °F), and low dissolved solids. Regular water changes to maintain low nitrate are essential for all Hypostominae. Feeding protocols for related Peckoltia — high-quality sinking pellets, wafers, blanched vegetables, and occasional protein foods — should transfer directly to this species. Until captive breeding is documented, no species-specific breeding advice can be offered responsibly.
Conservation
Peckoltia greedoi has not been assessed by the IUCN Red List as of this writing (listed as 'Not Evaluated' on PlanetCatfish). The species is known from a single collection event at a single locality in 1998 — the Río Gurupi at the BR 316 crossing, Pará–Maranhão state border — and no subsequent field collections have been reported in the published literature.
The Río Gurupi basin in eastern Pará and Maranhão faces significant pressure from deforestation and associated habitat degradation. The Para–Maranhão border region has been one of the most heavily deforested areas in the Brazilian Amazon frontier over the past several decades, with agricultural expansion and road infrastructure driving riparian forest loss and increased sediment and agricultural runoff into freshwater systems. For a species known from only one point on one river, any significant alteration of the Gurupi at or near the type locality represents a potential threat.
Given the species' restricted known range, extreme rarity of collection records, and the documented pressures on its habitat, a formal IUCN assessment using available data would likely result in a Data Deficient or Vulnerable evaluation. GBIF and FishBase hold no occurrence records beyond the type locality. Targeted surveys of the Gurupi drainage for this and related loricariids would be a research priority for any Hypostominae conservation programme in eastern Brazil.