SCOTCAT.COM  

or our first factsheet of 2004 we shine the spotlight on a species that could be deemed as one of the most dangerous freshwater catfish kept by aquarists. So as not to alarm unsuspecting keepers of this animal, the dangerous bit concerns the poison that can emanate from a gland on the pectoral fin spine and has been known to be fatal to some humans. If stung you should immerse the wound in very hot water so as to dissipate the poison and then get in touch with your local doctor.

Heteropneustes fossilis

Now that we have scared the living daylights out of you :-) we shall commence with a few facts on the Asian Stinging Catfish. This catfish for many years was in its own family, Heteropneustidae, and it is only very recently that it has been moved into the Clariidae family (Diogo, R., M. Chardon & P. Vandewalle, 2003) which many in the scientific community thought that is where it should be. There are differences between the two families listed below. This does mean now that the family Heteropneustidae is now invalid and is such retired (see 2021 update at bottom of text).

Heteropneustidae: Short dorsal fin, two elongate pulmary sacs that run backwards from the gill through the muscles in the back.

Clariidae: Dorsal fin, large with many rays. Possess a much reduced air-bladder and their gills are stiffened to prevent their collapse when out of water and in a special part of the gill chamber are spongy arborecent (tree-like) organs growing from the upper ends of the gill arches.

Heteropneustes fossilis has the same attributes as the many Clariid species in that it can leave its chosen home and cross overland to an other body of standing water. This is helped by its body mucus which helps it from drying out

Heteropneustes fossilis - head view

Depending on whose thoughts that you attain to, there is one other species in this family, Heteropneustes microps. The reason that I mention this is there is another theory that microps is a junior synonym of fossilis and they are one and the same fish. The for fraternity state that the difference is that H.fossilis has a separation (notch) between the caudal and anal fin and that H.microps has these two fins joined together. The against faction say that the the fusion of these two fins can be caused by injury and therefore are one and the same species (Rohan Pethiyagoda and Mohomed M. Bahir 1998).

Line drawing of Heteropneustes fossilis showing the notch between the anal and caudal fins.

Image of Heteropneustes microps with fusion of the anal and caudal fins

All in all, not your usual catfish for the beginning hobbyist but something unusual for the experienced catfish keepers amongst us, and also a good challange for a breeding project. Give them a try.

The above image shows an unusual catch, a wild caught albino captured by fish importer Thomas Kobe.

Update 2021: The genus Heteropneustes has been removed from the Clariidae family and reinstated to the Heteropneustidae Hora, 1936 and H. microps has now been deemed to be a synonym of H. fossillis.

Asian stinging catfish, Fossil cat

Silurus fossilis, Saccobranchus fossilis, Silurus singio

-

South America: Pakistan and Sri Lanka to Myanmar. Type locality: Tranquebar.

30.0cm. (12ins)

21-25°C (69-77°F)

Body elongate, compressed. Abdomen rounded. Four pairs of barbels, one pair = maxillary; one pair = nasal; two pair = mandibular. Rayed fin short with 6-7 rays. Anal fin long with 60-79 rays. Ventral fins 6 rays. Two elongate pulmary sacs that run backwards from the gill through the muscles in the back.

Apart from giving it the utmost respect when handling, it does very well in a larger aquarium, and you can either keep it alone with other inhabitants that are too big for its mouth (large Barbs, Cichlids etc.) or in a group situation if you would like the challenge of breeding them. A sand substrate is best with hiding places of rock and cavework and making sure that it has plenty of swimming space, as they do like to cruise the tank during the nightime hours. Keep your regular water changes up with good filtration as they are a greedy species, and can make a mess of your aquarium if good husbandry is not adhered to.

Has been reportedly bred in the aquarium where they excavate a nest in the substrate and the parents look after and defend the eggs. The young when born are guarded throughout their early development and can be fed Brine shrimp naupli and tablet food.

The females are stockier looking than the males.

Will eat almost anything such as tablet and pellet foods. Will also much appreciate some live foods such as garden worms and other wormlike food. Frozen bloodworm is another good bet. Experiment with feeding to find the right balance.

Heteropneustes: From the Greek heteros meaning other; Greek, pneo = to breath (atmospheric air)
fossilis: Ancient.

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.
Diogo, R., M. Chardon & P. Vandewalle, 2003. Osteology and myology of the cephalic region and pectoral girdle of Heteropneustes fossilis (Teleostei: Siluriformes), with comments on the phylogenetic relationships between Heteropneustes and the clariid catfishes. Animal Biology, 53: 379-396.
Jayaram, K.C. The Freshwater Fishes of India. Zoological Survey Of India, Calcutta.
Pethiyagoda, Rohan and Bahir, M. Mohomed; Heteropneustes microps, a junior synonym of H. fossilis (Osteichthyes: Heteropneustidae) 1998. Wildlife Heritage Trust of Sri Lanka.

Photo Credits

First and second images: © Johnny Jensen @
Bottom image: Sridhar Sivasubbu from image at Fishbase
Line Drawing: (After Misra, K.S. 1962, text-fig. 104)
Albino image: © Thomas Kobe