What is Datnioides undecimradiatus?
Datnioides undecimradiatus is a species of freshwater
ray‑finned fish, commonly known as the Mekong tiger perch or “thin‑bar
datnoid.” It belongs to the genus Datnioides, which is often placed in
the family Lobotidae (or in some treatments Datnioididae) within
the order Lobotiformes. PubMed+3Wikipedia+3seriouslyfish.com+3
This species is characterized by a deep, laterally
compressed body, vertical dark bars on its sides (narrower and fewer than in
many congeners), and a particular fin ray structure: dorsal spines, soft dorsal
rays, anal spines, and soft anal rays in fixed numbers. The body depth is about
2.1–2.4 times in the standard length (i.e. the fish is fairly deepbodied) FishBase+2seriouslyfish.com+2.
Maximum published standard size is about 40 cm (some sources slightly
less, depending on specimen) for male / unsexed individuals. fishbase.mnhn.fr+2seriouslyfish.com+2
The colouring includes four relatively thin dark vertical
bars; the first bar often doesn’t extend fully onto the ventral surface; the
second bar originates typically from the base of the 5th or 6th dorsal‑spine
region. The soft rays typically include ~11 soft anal rays in most individuals.
seriouslyfish.com+1
Diet: it is a predator, feeding on smaller fishes and
shrimps. seriouslyfish.com+1
Discovery: Who, When, and Where
- Who
discovered (described) it: The species was formally described by Tyson
R. Roberts and Maurice Kottelat. Wikipedia+2seriouslyfish.com+2
- Year
of description: 1994. Wikipedia+1
- Original
name / synonym: Initially described as Coius undecimradiatus
Roberts & Kottelat, 1994. Later taxonomic revision placed it in Datnioides
when Coius was synonymized. Wikipedia+2seriouslyfish.com+2
- Type
locality: The description’s type locality is the Mekong River, a few
kilometres downstream from the Lee Pee (or Khone) waterfalls, in Laos. Wikipedia+1
Geographic Distribution and Habitat (Where It Lives)
- Range:
This species is endemic to the Mekong River basin (middle and lower
parts) in Indochina. It is found in Thailand, Laos, Cambodia, and
Vietnam. seriouslyfish.com+2FishBase+2
- Habitats:
- Prefers
large, deep, lowland freshwater rivers and major tributaries. Not
known to inhabit brackish or marine waters. seriouslyfish.com+1
- In
the Mekong and its tributaries: sections where water flow is substantial,
depth is good, with less disturbance tend to support this species. seriouslyfish.com+1
- Abundance
/ Areas of highest prevalence:
- It
is most common in parts of the Mekong basin where habitat remains
relatively intact and human disturbance is lower. Tributaries like the Mun,
Sekong, Xe Bangfai have records of occurence. seriouslyfish.com
- Studies
of growth from the Mekong and Mun Rivers indicate that both stocks exist;
so the Mun River stock is one of the more significant of its populations.
Thai Journal Online
Biological and Genetic Importance
- Datnioides
undecimradiatus is significant both ecologically and scientifically.
- Ecological
role:
- As a
predatory freshwater fish, it helps regulate populations of smaller fish
and crustaceans in its habitat, contributing to the trophic dynamics of
the Mekong River ecosystems.
- It
is part of the biodiversity richness of the Mekong basin, which is one of
the most globally important freshwater biodiversity hotspots. Its
presence is indicative of relatively healthy river systems.
- Genetic
/ evolutionary importance:
- Whole
genome sequencing has been done; a reference genome (~595 Mb) has been
assembled. This helps resolve phylogenetic relationships within Lobotiformes
and with other related groups like Sciaenidae and Tetraodontiformes.
PubMed+1
- The
mitochondrial genome has been sequenced as well. This provides molecular
data for phylogeography, evolutionary history, and helps in assessing
population structure. PMC
Conservation Status & Biodiversity Significance
- According
to FishBase, D. undecimradiatus is assessed as Vulnerable
(VU) on the IUCN Red List. Major threats include overfishing (both for
food and the ornamental/aquarium trade), habitat alteration (dams, water
infrastructure, removal of riparian vegetation), pollution, and general
habitat degradation. seriouslyfish.com+2Wikipedia+2
- Population
has been declining in many areas, especially where river regulation, human
population pressure, and trade pressure are high. seriouslyfish.com
- Because
of its restricted range (only in Mekong basin), dependence on riverine
habitat, and sensitivity to disturbances, the species is a useful
indicator of freshwater ecosystem health. Loss or decline of D.
undecimradiatus reflects broader impacts on aquatic biodiversity in
Southeast Asia.
Where Has It Lived the Most (Strongest Populations)
- Strongest
populations are in parts of the middle and lower Mekong basin in
relatively undisturbed tributaries and main channels. The Mun River
(Thailand) is highlighted in several studies (e.g. age/growth work) as
having a distinct stock. Thai Journal Online+1
- Also,
the species has been reported in tributaries such as Sekong, Xe Bangfai.
These are among areas where habitat allows enough depth, flow, and prey to
sustain them. seriouslyfish.com
Summary
In summary:
- Datnioides
undecimradiatus is a freshwater predatory fish described in 1994 by
Roberts & Kottelat, endemic to the Mekong River basin in Indochina
(Laos, Thailand, Cambodia, Vietnam).
- It is
biochemically and genetically well‑studied, which aids understanding of
fish evolution and river ecology.
- It is
important for its ecological role, its value in the aquarium trade, and as
a conservation indicator species.
- It
lives mostly in large, deep, flowing rivers and major tributaries;
populations are strongest in less‑disturbed catchments (e.g. Mun River).
- The
species is vulnerable due to human threats, and its continued decline
would reflect negative environmental changes in the Mekong system.
📚 References
- Roberts,
T. R., & Kottelat, M. (1994). Description of a new species of
tiger fish from the Mekong River.
- Original
description of Datnioides undecimradiatus (as Coius
undecimradiatus).
- Source:
Taxonomic publication (journal details not always publicly accessible).
- FishBase
(2025). Datnioides undecimradiatus species summary.
- Retrieved
from: https://www.fishbase.se/summary/Datnioides-undecimradiatus.html
- SeriouslyFish
(2024). Datnioides undecimradiatus profile.
- Comprehensive
data on distribution, ecology, and aquarium trade.
- Retrieved
from: https://www.seriouslyfish.com/species/datnioides-undecimradiatus
- Wikipedia
Contributors (2025). Datnioides undecimradiatus.
- Background
and taxonomic information.
- Retrieved
from: https://en.wikipedia.org/wiki/Datnioides_undecimradiatus
- Xie,
M. et al. (2020). A chromosome-level genome assembly of tiger perch
(Datnioides undecimradiatus).
- Scientific
Data, 7, Article 172.
- DOI:
10.1038/s41597-020-0510-6
- Jian,
Y., et al. (2020). The complete mitochondrial genome of Datnioides
undecimradiatus.
- Mitochondrial
DNA Part B, 5(4), 3995–3996.
- DOI:
10.1080/23802359.2020.1838280
- Phousavanh,
A. et al. (2016). Age and growth of Datnioides undecimradiatus in
the Mun River, Thailand.
- Journal
of Fisheries and Environment, 40(1), 57–64.
- Retrieved
from: https://li01.tci-thaijo.org/index.php/jfe/article/view/80919
