Your internet guide to
all things catfish

Pseudomystus siamensis  Regan, 1913 

his Bagrid has been a mainstay of the catfish hobby in the U.K. for many years now and you can still purchase them under the older genus name of Leiocassis the name that most aquarists will be more familiar with, so if you are looking for more info on this species in books, Leiocassis will do for a start. Pseudomystus was actually a subgenus of Leiocassis which K.C.Jayaram had placed siamensis in, in 1968, but is now a full genus name.

Pseudomystus siamensis


Below is the comparisons made by Jayaram taken from "The Atlas of Freshwater and Marine Catfishes" by Dr.Warren E.Burgess.
1a. Snout angular and produced beyond the inferior mouth; snout length greater
than interorbital width..........Leiocassis.
1b. Snout rounded or obtuse, not produced beyond the subterminal mouth; snout length equal to or less than interorbital width..........Pseudomystus.

It sometimes gets sold as
Pseudomystus stenomus (again known in shops as Leiocassis) in some aquatic outlets but the colouration is different (stenomus does not sport banding in the body) and siamensis grows larger and is more predatory towards smaller tankmates. It is known under its common name of the "Asian Bumblebee Catfish", it is nocturnal and can be territorial with others and its own kind and will prowl the tank after lights out, so I would definitely not house them with smaller fish as they will view them as a snack!. They can also nip the fins of larger species, so keep well fed with a feeding after lights out to curb this aggression, but in saying that they are a favourite fish with myself and other catfish enthusiasts and it is worthwhile to find a niche in your (larger) community tank for this species. It is very hardy in a aquarium setting relating to water temperature and p.H. having a tolerance to a wide spectrum of water conditions, but of course not as extreme as to cause stress.

Pseudomystus siamensis

Stamp of Thailand showing this species

Found in Rivers and streams of the Mekong and Chao Phrya basins along with the rivers that empty into the Gulf of Thailand.

Dorsal spines (total): 1-1; Dorsal softrays (total): 7-7; Anal soft-rays: 16-17. short barbels (maxillary barbels not reaching base of pectoral spine); body depth at dorsal-fin origin larger than head width; a high, rounded adipose fin.

Irregular vertical bars on a yellowish to dark grey background (sometime plain dark body); hyaline caudal fin with or without a single black blotch on each caudal lobe.

Can be kept in a community tank but would watch if housing an adult with smaller Characins or Livebearers as they could be picked of at night when it starts cruising the tank. They can also nip the fins of larger species, so keep well fed with a feeding after lights out to curb this aggression.

Not reported but would appear to be a substrate spawner laying its eggs in tangled roots in the wild, I guess the p.H.would need to be on the acid side for any success with this species. There is a fleshy appendage in front of the anal fin that would indicate sexual dimorphism which has been noticed in other Bagrids.

In its native habitat it feeds on aquatic insect larvae including odonatans. A wide variety of foods can be given in the aquarium as this species is not fussy as long as it is fed, preferably after lights out. If you know where it hides out during the day you can drop tablet food, frozen food etc.into its resting place underneath stones/slates or bogwood.

Pseudomystus: False Mystus.
siamensis: From Siam (Thailand)

Close, But No siamensis.

Burgess, W.E., 1989 An Atlas of Freshwater and Marine catfishes: a preliminary survey of the Siluriformes. T.F.H. Publications, Neptune City, New Jersey
Baensch, H.A. and R. Riehl
1985 Aquarien atlas. Band 2. Mergus, Verlag für Natur- und Heimtierkunde GmbH, Melle, Germany. 1216 p.
Linder, Shane: Catfish Mailing List 1998.
Rainboth, W.J. 1996 Fishes of the Cambodian Mekong. FAO Species Identification Field Guide for Fishery Purposes. FAO, Rome, 265 p.
at www.fishbase.org

Photo Credits
© Ian Fuller @CorydorasWorld
Factsheet 24

Leiocassis siamensis, Leiocassis albicolaris, Leiocassis albicollis, Leiocassis bicolor  
Common Name:
Asian Bumblebee Catfish
Thailand Thailand: Mekong and Chao Phraya River basins and peninsular Thailand. Type locality: Bangpakong River, Siam.
16cm ( 6¼ins)
21-26°C (70-79°F)
6.0 - 8.0
If you found this page helpful you can help keep ScotCat running by making a small donation, Thanks. 

Donate towards my web hosting bill!


Print Friendly and PDF































































                                                                                                               Factsheet 24= updated January 2, 2005, © ScotCat 1997-2018 Go to Top