Catfish · Driftwood cats

Liosomadoras morrowi

Fowler, 1940

Morrow's driftwood catfish

IUCNLEAST CONCERN
CARESNOT LISTED
Scientific size6 in15 cm standard length
Temperature68–77 °F20–25 °C
pH6–7neutral
Depthnot recorded
DietNocturnal benthic omnivore/micro-predator — aquatic invertebrates (bloodworm, earthworms) taken after dark; will consume small fish under cover of darkness. In the aquarium takes sinking pellets, frozen and live foods offered after lights-out
BreedingInternal fertilisation via the modified male anal fin; female stores sperm and spawns later. Not known to have been bred in the home aquarium.
Sexual dimorphismYesMales bear a modified, elongated anal fin (intromittent organ) used for internal fertilisation; not otherwise well documented
PhotographsSee photosGoogle Images →

Liosomadoras morrowi is a small South American driftwood catfish, a nocturnal wood-and-bark forager from the Ucayali River system of Peru that spends its days wedged into cover and its nights combing the bottom for invertebrates. Like the rest of the family Auchenipteridae, it breaks with almost every other catfish in the hobby on one point: fertilisation is internal, the male passing sperm to the female with a modified anal fin so that she can store it and lay fertile eggs later, a strategy that also means the species is essentially never bred in home aquaria.

What's in the name

Liosomadoras morrowilee-oh-so-ma-DOR-as MOR-roh-eye

Liosomadoras
  • leiosGreeksmooth
  • somaGreekbody
  • DorasGreek/genusreferencing the catfish genus Doras — together, a 'smooth-bodied Doras-like' catfish
morrowi
  • morrowiLatinised eponymhonours Morrow, the collector/naturalist associated with the type material

Taxonomy & naming

Liosomadoras morrowi was described by the American ichthyologist Henry Weed Fowler in 1940. It belongs to the family Auchenipteridae, the driftwood catfishes, a mostly South American group distinguished among catfishes by internal fertilisation. The genus Liosomadoras is small, and the Catalog of Fishes treats Liosomadoras morrowi as the currently valid combination.

Auchenipterid taxonomy has been reshuffled repeatedly as the family's genera were revised through the twentieth century, and older literature on driftwood catfishes sometimes used different generic placements for related species; morrowi itself has remained in Liosomadoras. The genus name combines Greek roots referring to a smooth body, and the species epithet honours the collector or naturalist Morrow associated with the type material.

Morphology

Liosomadoras morrowi is a modestly sized, elongate catfish reaching a maximum of about 6 in standard length — a genuinely small driftwood cat rather than one of the larger auchenipterids that outgrow typical home tanks. The body is smooth-skinned and scaleless, like virtually all catfishes, with the naked skin that makes this group more sensitive to copper-based and some other medications than scaled fish.

As in other Auchenipteridae, the dorsal and pectoral fins carry stiff, serrated spines that can lock erect; these catch in aquarium nets and can jab a careless hand, so the fish is best scooped and moved in a container rather than netted. Coloration is a plain, cryptic brown-to-grey suited to life tucked among submerged wood and leaf litter, and males of the family bear the modified, elongated anal-fin rays used to transfer sperm during mating.

Habitat

The species is a South American endemic known from the Ucayali River system in Peru, part of the upper Amazon basin. It lives among submerged driftwood, root tangles and leaf litter in flowing forest rivers and streams, the tangled cover that gives the whole family its common name.

Water in its native range is warm and on the soft, slightly acidic side: Seriously Fish gives a temperature range of 68–77 °F, pH 6.0–7.0 and hardness of 2–10°H. It is not a hard-alkaline fish, and it does best in a well-filtered, gently flowing setup that echoes the oxygenated, structurally complex rivers it comes from rather than a still, decor-light tank.

Feeding

Liosomadoras morrowi is a nocturnal benthic omnivore, foraging along the bottom and among wood after dark for aquatic invertebrates, and it is known to pick off small fish under cover of darkness. In its natural habitat this opportunistic diet likely also includes fallen fruit, seeds and detritus typical of Amazonian driftwood-cat diets.

In the aquarium it takes bloodworm, earthworms and other frozen or live invertebrate foods readily, along with sinking pellets. Because it is strictly nocturnal, food is best offered after the lights go out or the tank is dimmed, so it is not out-competed by diurnal tankmates and has the confidence to leave cover and feed.

Mating

Driftwood catfishes of the family Auchenipteridae are one of the very few catfish groups with internal fertilisation, and Liosomadoras morrowi follows that pattern. The male's anal fin is modified into an intromittent organ used to transfer sperm directly into the female during mating, rather than the eggs being fertilised externally over open substrate as in most catfishes.

Following mating the female is able to store the sperm internally and lay fertilised eggs some time afterward, decoupling spawning from egg-laying in a way that is unusual among fishes generally, let alone catfishes. This biology has been documented for the family but the finer details of courtship and mate choice in this particular species are not well studied.

Breeding

Liosomadoras morrowi is not known to have been bred in the home aquarium. As in other Auchenipteridae, fertilisation is internal via the male's modified anal fin, and the female stores sperm before laying eggs later; this decoupling of mating from spawning, combined with the species' nocturnal, secretive habits, makes reproduction very difficult to observe or manage in captivity.

Parental care after spawning is not documented for this species, and given the internal-fertilisation strategy the male plays no further guarding role once mating has occurred. Aquarists should not expect to breed this species, and any reports of spawning would represent a genuinely rare event worth documenting carefully.

In the aquarium

This is a small driftwood catfish — a real adult length of about 6 in SL rather than one of the larger auchenipterids — so it suits a modestly sized aquarium furnished with driftwood, root tangles, leaf litter and other cover it can retreat into by day. Keep the water warm and on the soft, slightly acidic side (around 68–77 °F, pH 6.0–7.0, 2–10°H) with gentle to moderate flow and dim lighting; it is strictly nocturnal and rarely shows itself under bright light.

Because it is scaleless, dose copper-based and other medications conservatively, as with loaches, puffers and other naked-skinned catfishes. Its dorsal and pectoral spines lock and can snag a net or jab a hand, so move it in a container rather than netting it directly. It will take small fish after dark, so choose tankmates too large to be considered prey, and feed it after lights-out so it is not out-competed by more visible, daytime feeders.

Conservation

The IUCN Red List assesses Liosomadoras morrowi as Least Concern. It is known from the Ucayali River system in Peru, part of the vast upper Amazon basin, and is not currently considered at elevated risk of extinction.

As with many small, wood-dwelling Amazonian catfishes, detailed population data are limited, and the species' fortunes are tied to the health of its native river and floodplain-forest habitat. General Amazonian pressures — deforestation, water-quality change and habitat disturbance along tributary rivers — are the relevant long-term concerns even where the current assessment is favourable.

Sources

  1. FishBase — Liosomadoras morrowi Fowler, 1940
  2. IUCN Red List — Liosomadoras morrowi
  3. Seriously Fish — Liosomadoras morrowi profile
  4. ScotCat Factsheets — Liosomadoras morrowi

Last reviewed 2026-07-01.

How to cite

Aquarist Atlas (2026). Liosomadoras morrowi. Aquarist Atlas.https://www.aquaristatlas.com/catfish/liosomadoras-morrowi/

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