Taxonomy & naming
Barbodes resinus was described by the American ichthyologist Albert William Herre in 1924 from specimens collected in Lake Lanao and the Agus rapids on Mindanao. The original description placed the species in a combination that was later transferred; it is also known in the literature under the synonym Mandibularca resina Herre, 1924, reflecting the complex taxonomic history of the Lake Lanao barb flock. The Catalog of Fishes (Eschmeyer, CAS) records the valid combination as Barbodes resinus (Herre, 1924), with the parenthetical authority marking its removal from Herre's original genus.
The genus Barbodes Bleeker, 1859 is a large Asian clade within the family Cyprinidae. Lake Lanao harboured an extraordinary adaptive radiation of Barbodes barbs — seventeen species found nowhere else on Earth — that arose in isolation in the lake's geologically young but ecologically rich waters. Barbodes resinus was distinguished from its congeners by its large body size, representing the apex of the radiation in terms of overall mass. It is now regarded as Extinct, and its scientific name survives chiefly in museum records and conservation literature documenting the loss of the Lanao endemic fish community.
Morphology
Barbodes resinus reached a maximum recorded total length of 8.5 in, making it the largest cyprinid in Lake Lanao and one of the more substantial members of the genus Barbodes. FishBase records a benthopelagic lifestyle and a trophic level of 2.7, consistent with a low-trophic omnivore or detritivore exploiting the lake's deeper water column and substrate near the outflow rapids.
Detailed morphological data in the published literature are sparse for this species, reflecting the limited collection effort before the population's collapse. Like other members of the Lake Lanao barb flock it would have carried the typical cyprinid body plan — a streamlined, laterally compressed form with cycloid scales, a terminal or subterminal mouth, and the small barbels characteristic of the genus. The combination of large size and benthopelagic habit suggests it was an ecologically distinct component of the lake's trophic structure, occupying a niche separated from the smaller, more littoral members of the radiation.
Habitat
Lake Lanao sits at approximately 2303 ft above sea level in the Lanao plateau of Mindanao and is one of the oldest and deepest lakes in the Philippines, with a maximum depth exceeding 328 ft. It is an ancient, isolated lake with a warm, tropical thermocline and broadly neutral pH; water chemistry data inferred from the lake environment suggest temperatures in the range of 79–82 °F and a pH near 7.4, with moderate mineral content typical of upland Philippine freshwater.
Barbodes resinus was specifically associated with the benthopelagic zone and with the Agus rapids, the lake's sole outflow, rather than the shallow littoral margin occupied by many of its smaller relatives. This habitat association may have made it particularly vulnerable to changes in the outflow regime and to pressure in the open-water fishing zones. The species was never recorded from rivers or other water bodies — its entire known range was the lake itself and its immediate outlet.
Feeding
FishBase records a trophic level of 2.7 for Barbodes resinus, placing it among low-level consumers typical of cyprinids that exploit a mixed diet of invertebrates, plant matter, detritus, and algae. No detailed stomach-content studies have been published for this species, and the sparse literature on the Lake Lanao barb flock as a whole leaves feeding ecology poorly documented.
By analogy with similarly sized Barbodes and with what is known of the Lanao radiation, B. resinus likely foraged in the water column and along the benthos near the rapids outflow, taking whatever invertebrates, organic particles and algae were available. The benthopelagic designation from FishBase suggests a fish comfortable in open water above the substrate rather than a strict bottom-feeder — consistent with a generalist feeder exploiting the productive, oxygenated water near the lake's outflow.
Mating
No direct observations of courtship or spawning in Barbodes resinus have been published. Like all members of the family Cyprinidae, it was almost certainly an egg-scattering, non-guarding spawner. Barbs do not build nests, hold territories beyond the immediate act of spawning, or exhibit any form of parental care: courtship consists of males pursuing gravid females through the water column or over the substrate, with eggs and milt released together in brief, repeated contacts.
For the larger-bodied members of the genus Barbodes, and for benthopelagic lake fishes more generally, spawning likely involved open-water broadcast of adhesive or semi-adhesive eggs that settled among rocks or substrate near the outflow. No nest, pair bond or guarding behaviour is known or expected for any barb.
Breeding
Reproductive biology specific to Barbodes resinus is undocumented; the species became extinct before systematic study of its life history was possible. Extrapolating from the barb reproductive template, females would have been capable of producing multiple clutches per season, scattering adhesive eggs that received no parental attention after deposition. Incubation and larval development in warm Lake Lanao water (79–82 °F) would have proceeded rapidly by the general cyprinid pattern.
The species was never maintained or bred in captivity. The collapse of the Lake Lanao endemic barb fauna occurred so rapidly — driven by overfishing, predation from introduced species such as flowerhorn cichlids and snakehead, and progressive habitat degradation through the mid-to-late twentieth century — that no ex-situ conservation effort was mounted in time for B. resinus or the majority of its congeners.
In the aquarium
Barbodes resinus was never established in the aquarium hobby. Its relatively large size (8.5 in TL), benthopelagic lake habits, and restriction to a single remote Philippine lake made it unlikely to appear in the trade; and the collapse of the Lake Lanao fish community preceded any serious hobbyist or institutional interest in the Lanao barb flock as aquarium subjects.
No captive population exists anywhere. The species is recorded as Extinct on the IUCN Red List assessed in 2020, and there is no known surviving ex-situ stock that could serve as the basis for a recovery or reintroduction programme. Its closest known relatives are the few surviving members of the Lake Lanao Barbodes radiation, some of which may also face extinction.
Conservation
Barbodes resinus is assessed as Extinct (EX) on the IUCN Red List, with the assessment year recorded as 2020. It is one of fifteen to sixteen of the seventeen Lake Lanao endemic barb species now considered extinct — a freshwater biodiversity loss of exceptional magnitude concentrated in a single lake. The proximate drivers were multiple and synergistic: intensive gill-net and electrofishing pressure targeting the larger-bodied species such as B. resinus, the introduction of predatory and competing alien fishes (most notably the flowerhorn hybrid cichlid, snakehead Channa, and Nile tilapia), and progressive degradation of water quality from agricultural run-off and inadequate sewage treatment in the Lanao watershed.
The loss of the Lanao barb flock represents one of the most severe freshwater extinction events in recorded history. Conservation assessments noted the completeness of the collapse — surveys conducted in the late twentieth and early twenty-first centuries failed to locate living specimens of any of the critically declining Barbodes endemics despite targeted effort. No recovery plan for Barbodes resinus is feasible in the absence of any surviving individuals.