Common Woodcat, Stor Drivtømmermalle (Denmark) - Trachelyopterus galeatus (Linnaeus, 1766)
Article © Julian Dignall, uploaded July 01, 2000.
Ugly or beautiful? Opinion is commonly divided between these two poles when aquarists talk about catfish. Often it is the case that the appreciation of a particular catfish comes with the familiarity of keeping one. Take this woodcat, at first (and for some people always) this fish is plain ugly. It has a belligerent, troublesome look with its low slung eyes and thick lower lip. Familiarity however gives us the pleasure of witnessing the fishes enthusiastically boisterous character. In good condition many of these fish exhibit a very pleasant gold and tan colouration.
Colouration is key to this fish; it has set out to imitate a piece of wood and certainly succeeds. Youngsters especially are hard to spot and spend most of their time crammed into woody crevices. The pattern and colouration of this fish is very variable. Firstly, amongst individuals as environmental parameters such as water and lighting change. Secondly, in the wild it has a huge distribution range of pretty much most of tropical South America. This gives rise to many regional colour variations and is, in part, to blame for the vast array of synonyms the fish has collected.
This fish is sometimes called the starry woodcat, which comes from one of the darker colour forms which exhibits white Van Gogh-esque "starry night" spots along the top half of it's head and upper back. This is set against a dark grey/brown background colouration. This fish pictured here is more golden brown and the spots are difficult to pick out. This common name also throws it into confusion with a few other woodcats and is not used here.
In the aquarium these fish spend most of their daytime inactive. They quickly become accustomed to your feeding routine and, if you feed at set times each day, will become restless in anticipation. Feeding is when you will see these fish during the day; they become quite fearless when food is on the agenda. The fish occasionally make quiet rodent-like squeaking sounds when perturbed, but this isn't common and, short of removing the fish from the water, only happens when a group of fish are present and a cave dispute breaks out.
Although you don't see these fish during the day, the way to keep them is in numbers. They are relatively easy to sex andmost likely have very interesting reproductive techniques that we know very little about. Growing a group up together is the best way to ensure a pair is present and these fish do seem to enjoy each other's company during their brief periods of activity.
Copyright information for the images used in this article can be found on the species' full Cat-eLog page.
|Cat-eLog Data Sheet|
|Scientific Name||Trachelyopterus galeatus (Linnaeus, 1766)|
|Common Names||Common Woodcat
Stor Drivtømmermalle (Denmark)
|Type Locality||South America [possibly Suriname River].|
|Synonym(s)||Auchenipterus maculosus, Parauchenipterus galeatus, Parauchenipterus paseae, Pseudauchenipterus galeatus, Silurus galeatus, Trachycorystes galeatus|
|Pronunciation||gal ee ATT uss|
|Etymology||Trachelyopterus: From the Greek, trachelos, meaning neck and pteron, meaning fin; in reference to the long cranial shield, which gives the appearance that the dorsal fin originates at the neck region.|
|Size||237mm or 9.3" SL. Find near, nearer or same sized spp.|
|Identification||Colouration is key to this fish; it has set out to imitate a piece of wood and certainly succeeds. Youngsters especially are hard to spot and spend most of their time crammed into woody crevices. The pattern and colouration of this fish is very variable. Firstly, amongst individuals as environmental parameters such as water and lighting change. Secondly, in the wild it has a huge distribution range of pretty much most of tropical South America. This gives rise to many regional colour variations.|
|Sexing||Male has a slightly concave anal fin, which is slightly convex in the female. The leading rays of the male's anal fin are fused to form a urinogenital organ used in internal fertilization of the female. This modification of the anal fin does not manifest itself until the fish is at least 75% grown.|
|Distribution||Widely distributed in the Amazon and is found from the Northern tip of South America as far South as tropical Peru and Brazil.
Amazon (click on these areas to find other species found there)
Guyana Waters, Coastal Rivers of Guyanas, Suriname Coastal Rivers, Marowijne, Upper Marowijne, Grand Inini (click on these areas to find other species found there)
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|IUCN Red List Category||Not Evaluated|
|pH||6.0 - 7.5|
|Temperature||20.0-24.0°C or 68-75.2°F (Show species within this range)|
|Other Parameters||Slightly soft water is preferable but in no way vital - this is a hardy fish.|
|Feeding||Most prepared foods are taken. Live or frozen foods will promote fast growth although are not necessary to maintain this fish in good condition. Care should be taken not to feed dry foods which expand after contact with water. This fish is a glutton and will eat all food present; if this subsequently expands inside the fish it may cause internal injury. Presoak these foods before use.|
|Furniture||Juveniles (smaller than 2'') require tangles of bogwood within which to hide. Floating plants or clumps of Java moss are also helpful. Larger fish require a cave each and this is most easily achieved with lengths of black PVC drain pipe.|
|Compatibility||A boisterous fish that likes to throw its weight around but in no way aggressively. Smaller fish are at risk purely because of the fishes large mouth and nocturnal prowling.|
|Suggested Tankmates||A boisterous fish that likes to throw its weight around but in no way aggressively. Smaller fish are at risk purely because of the fishes large mouth and nocturnal prowlings.|
|Breeding||Not recorded in the aquarium. As mentioned before internal fertilization is utilized by this and most other genera in this family of catfish. The male internally produces a jelly-like substance which carries and protects his sperm once it is transferred to the female via the modified anal fin. Females can carry this sperm for up to 4 months before it is actually used in egg-laying. The male is not required and isn't usually present at this time.
Two female fish in a UK Public Aquarium spawned in the absence of a male, producing huge numbers of gelatinous eggs, sufficient to form a layer several eggs thick over a considerable area of the base of a 1000 gallon aquarium. It is assumed that the eggs swell considerably once they have left the body of the female. It would appear that the gelatinous coating provides protection from fungal or bacterial invasion, as in spite of being infertile they took longer than expected to decay.
|Breeding Reports||There is no breeding report.|
|Reference||Systema naturae sive regna tria naturae v. 1 (pt 1), pp 503|
|Registered Keepers||Keeping this species? Why not .
There are 21 registered keepers, view all "my cats" data.
|Wishlists||Love this species? Click the heart to add it to your wish list.
There is but a single wish to keep this species, see who wants what.
|Spotters||Spotted this species somewhere? Click the binoculars!
There are 17 records of this fish being seen, view them all.
|More on Trachelyopterus galeatus|
|Look up Trachelyopterus galeatus on AquaticRepublic.com|
|Look up Trachelyopterus galeatus on Fishbase|
|Look up Trachelyopterus galeatus on Encyclopedia of Life|
|Look up Trachelyopterus galeatus on Global Biodiversity Information Facility|
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|Last Update||2020 Aug 08 09:12 (species record created: 2000 Jul 01 11:22)|
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