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Mystus bocourti  (Bleeker, 1864)    

e all love bagrids don't we?. Here is another which sports a very impressive looking extended dorsal fin and your usual slate grey body colour, Mystus bocourti which can still be found in publications under its old name of Heterobagrus bocourti which is now a synonym.




Mystus bocourti in the aquarium


Mystus bocourti  in the aquarium


This species is distinguished from all other Mystus (indeed, from all other Asian Bagridae except Bagrichthys hypselopterus) by its extraordinary high dorsal fin, involving great elongation of the non-serrate dorsal fin spine and first three or four soft rays. Occurs in medium to large-sized rivers. M. bocourti is found in the Chao Phraya and Mekong basins, in Cambodia, Lao PDR, Thailand and Viet Nam.


Mystus bocourti in the field


Mystus bocourti  in the field


M. bocourti has been assessed by the IUCN Red List of Threatened Species as vulnerable because of an inferred population decrease of more than 30% in the past ten years (2009). This is as a result of high levels of pollution and hydrological alterations, including dams, in both the Chao Phraya and Mekong river basins.


There are a number of large dams and other water diversion projects which are an additional threat to M. bocourti in both the Chao Phraya and Mekong basins; effects of developments such as these to the freshwater ecosystem include alterations to the hydrological cycle, and changes to the levels of sedimentation and dissolved o². Dams also act as a physical barrier, which is especially pertinent to M. bocourti, a potamodromous species. More dams are currently under construction and planned for the future.



Dorsal spines (total): 2; Dorsal soft rays (total): 7; Anal soft rays: 10; Vertebrae: 43. Within Mystus sensu stricto, mouth relatively narrow. Caudal peduncle very slender with long and pointed lobes to caudal fin.

Dark brown dorsally, shading to grey/brown laterally and light ventrally. Sides and fin spines tinged with an iridescent green sheen. Faint mid-lateral stripe.

Aquarium Care

Can only be kept with the same or larger species as this bagrid, common with many from this family, can eat smaller fish. Keep either 3-5 specimens in a large tank with plants to the background. Substrate should be sand and provide hiding places with good filtration.



Not a community type catfish but can be kept with fish that are too large to be swallowed, i.e. over 10cm (4ins).


Not reported, but they are oviparous, distinct pairing possibly like other members of the same family.

Sexual Differences

Males have an elongate genital papilla in front of the anal fin. Females will be fuller bodied.



In its native waters the adults feed on crustaceans and benthic invertebrates. In the aquarium feed tablet and pellet foods, earthworms, and live and frozen foods. Not a fussy eater.

Glossary of Terms

Potamodromous: Freshwater fish migrations are usually shorter, typically from lake to stream or vice versa, for spawning purposes.
Dorsal fin: The primary rayed fin(s) on top of the body.
Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.
Sensu stricto: In a narrow or strict sense.
Synonym: Different name for the same fish.


Mystus: "Mystax" meaning whiskered (hair on the upper lip) Mystus was first used by Belon in 1553 to describe all fish with whiskers.
bocourti: In honour of Bocourt.


Baensch, H.A. and R. Riehl 1985 Aquarien atlas. Band 2. Mergus, Verlag für Natur- und Heimtierkunde GmbH, Melle, Germany. 1216 p.
Froese, R. and D. Pauly. Editors. 2009.FishBase. World Wide Web electronic publication. www.fishbase.org, version (12/2009).
Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Jenkins, A., Kullander, F.F. & Tan, H.H. 2009. Mystus bocourti. The IUCN Red List of Threatened Species 2009: e.T169548A6645864. http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T169548A6645864.en.
Roberts, T.R., 1994. Systematic revision of Asian bagrid catfishes of the genus Mystus sensu stricto, with a new species from Thailand and Cambodia. Ichthyol. Explor. Freshwat. 5(3):241-256.
Vidthayanon, Chavalit (2008) Field guide to Fishes of the Mekong Delta. Mekong River Commission, 288 pp.

Photo Credits

© Allan James @ ScotCat

© Jean-Francois Helias @
Fishing Adventures Thailand

Factsheet 241

Heterobagrus bocourti, Prajadhipokia rex
Common Name:
Hi fin Mystus
Asia: Mekong and Chao Phraya River basins. Type locality: Siam.
24cm (9½ins)
22-25°C (71-77°F)
6.5 - 7.5.
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