Article © Mika Kaukonen, uploaded January 01, 2006.
The first feature of 2006 is written by Mika Kaukonen. In his previous CotM article, Mika covered a Trichomycterid from Colombia, in something of a contrast, this month we travel half way around the globe to look at Glyptothorax.
At the time of writing, the catfish family Sisoridae contains 16 genera, 112 valid species and current estimates are of around 70 species waiting in the wings to be formally described. The family is widely distributed throughout the oriental region in southern Asia, from Turkey and Syria to South China and Borneo. Their length varies from tiny Nangra bucculenta 3,4 cm (TL) to 2m maximum length of the monstrous Bagarius yarelli. There are over 52 species of Glyptothorax although they usually originate from mountain rapids and fast flowing cool water areas. The smallest member is G. kapuri, 4 cm (TL) and biggest is G. coheni from India reaching up to 90 cm (TL).
It's reasonably well known that Glyptothorax (and other Sisorid genera) possess an adhesive apparatus in the thoracic region (chest). They use this to grip onto rocks in fast flowing rivers. Heok Hee Ng has recently written an article describing this and other methods of adhesion in catfishes. You can read it here.
In Finland, during the past five years or so, we have had an increasing number of imports from India and indeed Asia generally. Many previously unavailable and unfamiliar catfishes have turned up such as representatives from the Erethistidae, bagridae and the Sisoridae as I mentioned. Most of these are contaminants with no real market value. Some of them fit well to the average aquarium and others do not. Unfortunately I think all Glyptothorax species belong to latter group.
In autumn 2002, one wholesaler imported a batch of thirty fish labelled as Tatia sp. Later I was informed that the origin was either India or Singapore. At first glance in the fish store I saw that they were totally incorrectly identified. They were catfishes for sure, but that was about all that was correct, even their continent of origin was wrong!
So, I had the name Glyptothorax and little else. Aquarium literature was less than useful in this case. Several species are wrongly named and pictures present other than they supposed to. There were several alternatives to the name proposed here, like G. laosensis, G. trilineatus, G. cavia, G. lampris and G. pecinopterus. Still today I'm not convinced the true identity of my Glyptothorax.
These fish really stretch your skills as a fishkeeper. Basic rules for successful maintenance are an excellent dissolved oxygen level, cool temperature, good current and very clean water. Are there enough adjectives? Even this might not do the trick. Initially, everything depends upon the general condition they arrive. They do not travel well and most die within a month of captivity. Emaciation, internal damage (caused by lack of oxygen), stress of capture and travelling in poor conditions are probable main reasons for this. They seem to get bacterial infections for some time even if they seem settled down.
I reserved fifteen fish from my fish store and returned home to make preparations. Disaster soon struck - overnight at the fish store, the filter had stopped and when I checked them the next day I was down to only five survivors. All the other river catfish had perished, yet the other fishes seemed to be doing fine. Later that week I was able to get six more from another store. I housed them in an 100l aquarium in my office. It had one circulation pump with output of 1000 l/ h, diffuser and light. Temperature stayed around 22-23°C and there was no way I could get lower than that unless I kept a window open. In Helsinki it can drop to minus 25 ° and that is not so uncommon. If the temperature rises it cause Glyptothorax to "live faster" with the ultimate result of death by wearing itself out.
They second group seemed to settle down. The first days group of Glyptothorax remained stuck to the front glass, just in front of the powerhead outlet. They seemed to prefer blood worms and other frozen foods if available. Flakes and tablets were accepted as well. I changed 50% of water two times a week.
From the 11 individuals I now had, four decided to jump out of the tank in quick succession, two never started feeding and died in a week, four out of the remaining five fishes succumbed to some bacterial disease (very common in Glyptothorax spp.) and died in the second week. First I thought that they shed their skin, which is usual to sisoroid family. The last one however was living it up for the others. To my knowledge it still lives in the aquarium where it ended up after I sold it some time later.
While keeping this fish, I was intrigued by the skin shedding I had witnessed, when asked, Heok Hee gave the following response to my enquiry:
"Many sisoroids (aspredinids, sisorids, akysids and erethistids in particular) shed their skin because they have so much more keratin (they have a lot of epidermal structures made of keratin) than the average catfish skin (actually, sisoroid skin is more like mammalian skin than fish skin).
The way it works is also very much like our own skin...keratin is a protein that accumulates in dead skin cells, and through normal wear and tear, these skin cells slough off (a person sheds about 2 kilograms of dead skin every year). I'm not exactly sure why sisoroids would have skin like that (I suspect one reason is that the epidermal structures help keep the fish steady in fast-flowing streams by breaking up the laminar flow of water over them).
Anyway, the shedding only lasts one or two days in the Glyptothorax I have kept. During this time, they get harassed more than usual by tankmates, because they (the tankmates) seem to find the dead and peeling skin particularly tasty.
I wouldn't worry too much about the shedding...it seems to be a normal procedure (I have seen it in akysids I have kept as well) and the fish seems to suffer no ill effects from it."
In summary, if the mortality rate is like my experience i.e. one out of fifteen or even worse, should these cats to be left where they do belong - in nature? From my view, I must say that it is better to pass on these catfishes and enjoy them only in pictures.
Copyright information for the images used in this article can be found on the species' full Cat-eLog page.
Back to Catfish of the Month index.