Catfish of the Month Right Arrow September 2005 • Article © Julian Dignall, uploaded September 01, 2005



Parrot Doradid - Rhynchodoras woodsi   Glodek, 1976

On the eve of my departure for two weeks' "extreme R&R" on Caribbean shores, I sit down to write a catfish of the month. As ever, this begins with pondering what species to feature. Planet Catfish has been around for a long time now, these days it's easier to justify rambling on about some obscure favourite rather than find a more common species that, somehow, we've yet to feature. So, as perhaps that, or my impending holiday, has put me in a different frame of mind, I've gone for the obscure. Very obscure.

Those of you who were able to attend the Catfish Study Group Convention 2001 will have been treated to an excellent array of photographs taken by Erwin Schraml. Sadly, for several reasons, Erwin was unable to talk us through his wonderful photographs in person but, every cloud has a silver lining and this particular argent edge was that the job fell to one of THE names in the catfish world, Dr. Isaac Isbrücker. If you were there you would have also have heard Chris Ralph describe an expedition to South America where a number of CSG members (including the author) collected and imported Peruvian catfish. By sheer coincidence this article discusses species shown both in Erwin's slides and encountered on the Peruvian expedition; both talks were something of a catalyst.

These two species belong to the South American catfish family Doradidae, more commonly known as the talking, or thorny, catfish. The first species appears to be a fairly standard doradid (if there is such a thing) and, although uncommonly imported, is documented in most good commercial aquatic literature. The second is a real oddball and, I'm sure you'll get my meaning, is a real catfish person's catfish. I told you it was going to be obscure.

The intertwined story of these two fish begins in Peru. Prior to setting out on our boat-based collecting expedition our party took a look round some of Iquitos' fish exporters. These all too brief visits merit a short story in themselves but suffice to say that I lost count of the number of species of fish that I saw for the first time alive. Fish were grouped roughly a species per tank, bucket, pail or pool. Closer inspection usually showed that up to 4 or 5 different yet similar species were present in each container. Catfish were everywhere. Such was the impact on the senses that I missed things. Other members of the group appeared at my elbow, tugging my arm and saying, "come look at this"; it was heaven and hell. I had a video camera - both a blessing and a curse. A curse because I spent most of the time looking at the spectacular array of fish through a black and white viewfinder. A blessing because many of the fish overlooked at the time are now recorded for posterity on CD or website for all to see.

The collecting expedition, my first, was simply amazing. What's also amazing is how quickly you forget the bad bits. Safely home and reviewing one of the aforementioned videotapes I noticed that all was not equal in one tank of small doradids - although the fish were small some looked, well, odd. Now, even to a catfish fan, an odd Doradid is an odd fish indeed. This particular tank I remember because I bought 10 of the inch long fish within. They were purchased at the ludicrous sum of 50 US cents each - I didn't ask for a discount on numbers. Unfortunately I lost 6 of these either during or soon after return to Scotland (the return journey saw us fly with fish from Iquitos to Lima, an overnight in Lima, Lima to Atlanta, Atlanta to London and London to Edinburgh). The four survivors matched pictures of Rhinodoras dorbignyi (Kröyer, 1855) found in Baensch (Vol. 2 p499), Sands (Vol. 4 p39) & Schaefer (p88).

The second part of this tale begins in the UK, specifically Wigan, catfish Mecca of the North (of England). During a visit to Pier Aquatics I picked up a group of 10 larger doradids. I was interested in these fish because some looked like Rhinodoras and some did not. Those of you who gaze at shop tanks full of the same species in the hope of spotting something different will understand the excitement experienced when an entire half of the fish in there appear different.

The existing Rhinodoras were joined by their conspecifics and these new oddballs in a 3ft tank all of their own because all but the acclimatised fish were very skinny indeed. Some feeding up was required and, in the meantime, some research into what these other fish were was in order. I had been told that my new arrivals were exported from Lima, a common point of export for fish from Iquitos.

My search began by looking for Peruvian doradids. This turned out two things. Firstly, that Rhinodoras dorbignyi was described from the Rio de la Plata (River Plate) river system in Argentina / Uruguay. Nowhere near Iquitos in Peru and, indeed, a separate river system altogether. Secondly, I stumbled across a line drawing of Rhynchodoras xingui Klausewitz & Rössel, 1961 in the Burgess' Catfish Atlas (p205). This had to be at least the correct genus for my mystery doradid. Again, however, the locality didn't match at all. This species of Rhynchodoras is recorded from the upper Rio Xingu, Brazil. Although this is the Amazon River system it's half a continent downstream and hundreds of miles upstream.

In conversation with Robin Warne, another member of the Peru expedition, I was to learn that he had observed both these fish at an outlying (floating) collection station on the river. The local collectors stated that these two fish are found together in the wild. This is stronger detail than my video footage of them together at the exporters and their subsequent import into the UK together. It appears the two species are present together in the Peruvian Amazon. It is quite possible that the fish shown in some of the more recent publications as Rhinodoras dorbignyi are the Peruvian fish. After further digging, I came up with more described species from this genera. Erwin was to help with this and eventually I've come to calling the two species Rhynchodoras woodsi and Rhinodoras boehlkei. Leaving the taxonomy behind we can now focus on the husbandry of these two fish.

From an aquarist's point of view the Doradidae like many other catfish families can, if somewhat crudely, be halved into two groups. In one half we have the more familiar nocturnal, thorny or talking catfish types such as the evergreen Platydoras, Amblydoras or Agamyxis spp. They huddle together in packs during the day and cruise the aquarium, with surprising grace, after dark. They are opportunistic feeders and will eat huge amounts of virtually any food in one sitting given the chance. As I mentioned before the Rhinodoras or fog doradid (to use its descriptively apt common name) is a typical member of this group.

The second half of the family Doradidae is less commonly encountered for sale. They often go under the common name of mouse catfish. As with their rodent namesakes, these timid catfish tend to be more active during dawn and dusk than their nocturnal compatriots. Once settled in the aquarium they can be seen for most of the day. Although both groups of doradids are very sociable animals, many of the representatives of this second group appear to actively shoal when swimming. The most commonly encountered species belong to the genera Hassar, Opsodoras and Leptodoras (incidentally the CSG expedition in Peru encountered representatives of all of these genera). These fish appear smoother skinned and often have distinctive clusters of minutely feathered barbels. The best description I can think of is that these barbels resemble the tentacles of a squid.

My second species, the Rhynchodoras, doesn't sit quite right in either group. It does have the "squid face" of barbels belonging to the second group of doradids (although they are not feathered) but also possesses the more leathery, thorny flanks of the former. Both described Rhynchodoras spp. have tiny eyes, the smallest I have seen on any doradid (including Pterodoras), again at odds with the large eye of mouse cats. Additionally their behaviour in my aquarium to date is very much that of the former group. They rarely venture forth during the day and then only for food. Their day is spent closely squeezed into whatever preferably wood-based refuge is available, often two or three individuals in an impossibly small crevice.

Care of these two fish is also different. Rhinodoras are gregarious, easily fed fish. Some of the individuals have grown two inches or more in 6 months. Baensch lists their full-grown size as 6¾ inches — a reasonably sized fish for most aquarists and one that would seem likely given the fishes growth rate to date. They have a fleshy webbed base to their barbels, similar to adult Megalechis. Water parameters seem relatively unimportant especially once the fish has been acclimatised. Water temperature is 74°F. My group did well in a 3ft x 1ft x 1ft aquarium with some Corydoras and an almost random selection of Characins. Although initially kept successfully in a stronger water current, the current in their present surroundings is more in keeping with that expected of a Corydoras tank although both species have long cigar-shaped bodies and a curved dorsal spine. I also wonder about this; I thought it might be indicative of their life in a flowing river rather than forest stream?

This brings me onto an important point. Initially I kept these two species together in a similar sized aquarium. The Rhinodoras prospered but the Rhynchodoras appeared unsettled. Most of these fish looked fragile and certainly were not gaining weight. They appeared underfed on import and this situation had not changed with months of care. I decided to move out the prospering Rhinodoras and leave the Rhynchodoras to themselves. A month later the Rhynchodoras had shown signs of growth but were, if anything, even more secretive. Perhaps, being better fed, they are less desperate in their search for food. I started feeding heavily at night (quickly finding that flake food is largely ignored) mainly tetra prima and frozen brine shrimp or bloodworm. There is no trace of this in the morning.

Given their current growth rate, I do not feel that they will turn out to be one of the gentle giants of the family. Again they are being kept in neutral pH at a temperature of around 75F. To me they prefer a little more current and so I have a larger filter in their 3ft x 1ft x 1ft tank.

The Rhynchodoras appear to have a special affinity with wood. When I have watched them feed (at night) they search vertical surfaces first: feeding on the sandy substrate doesn't appear to come naturally to them. Aside from their very small eyes, perhaps the most unusual feature of these fish is a protrusion from their upper lip. Immediately in front of their barbels is an overhanging bony structure almost like a small pick. This puts me most in mind of a beaver's front bucktooth, although the structure is certainly not a tooth or teeth. Whether this is used as a pick in the search of food or simply protection for the delicate barbels in a strong current, I do not know. The fish favours eating at the intake of the internal filter. Here the fish can easily pick off trapped food; their oddly shaped mouths are perfectly adapted for the task. Perhaps in the wild these fish cruise submerged wood (tree trunks?) using their adapted mouths to search out small insects? It is this feeding behaviour that caused me to come up with a common name for these Rhynchodoras; Parrot doradid, at least to my eyes, perfectly describes the careful, rather quizzical search and inspection behaviour exhibited by this fish as it feeds; the parrot's beak being the odd mouth arrangement.

Neither fish are notably expensive or cosmetically striking. That is not to say that these fish don't both merit attention. Both are intriguing and certainly worth a look should you get an opportunity to keep them for yourself. Keeping these fish in numbers is the only way we have a chance of learning more than just how to keep them alive. Rhynchodoras has come to be a favourite of mine now as it completely epitomises everything great about being a catfish aficionado, as I said before, a catfish keeper's catfish.

References:
Dr. Rudiger Riehl & Hans A. Baensch. Aquarium Atlas Vol. 2. Tetra Press
Dr. David Sands. Catfishes of the World Vol. 4. Dunure Publishing
Dr. Burgess. An Atlas of Freshwater and Marine Catfishes. TFH.


Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

Jump to next section Cat-eLog Data Sheet
Scientific NameRhynchodoras woodsi  Glodek, 1976
Common NameParrot Doradid
Type LocalityEastern Ecuador
Pronunciationrink oh door add - woods eye
EtymologyRhynchodoras: From the Greek rhynchos, meaning nose, and doras, meaning skin (also a word commonly used in forming generic names for doradids); in refeence to the unusual snout morphology. 
Jump to next section Species Information
Size 110mm or 4.3" SL. Find near, nearer or same sized spp.
IdentificationThis species was considered extremely rare as late as 1992; at this time only 3 specimens were known from museum collections (the types of the two known species).>
The ichthyological discovery of Rhynchodoras actually dates back 150 years and is attributable to the British naturalist-explorer Alfred R. Wallace. From 1850-1852 Wallace traveled up the Río Negro in search of its headwaters and those of the Río Orinoco. During this expedition Wallace took notes on and prepared detailed drawings of the fishes collected. Although his collections were lost at sea, many of his notes and illustrations survived and are currently at the British Museum of Natural History. Notes that accompany Wallace's illustration of a species of Rhinodoras (originally labeled ''Doras'' and numbered 175) include the following comments (transcribed by M. Toledo-Piza Ragazzo): ''In a small specimen very closely resembling this [illustration of Rhinodoras] in all other particulars - the head is higher towards the snout which turns down and is produced in a sort of proboscis which is received in a ___ of ___ formed by the produced lower lip - the teeth are similar but are also continued in a row round the margin of each lip - perhaps this is the male - the above [Rhinodoras] being the female.'' This description was certainly based on a specimen of Rhynchodoras, the only doradid genus in which the snout ends in a vertically-oriented bill or ''proboscis'' formed by the upper and lower jaws.
SexingUnknown
Jump to next section Habitat Information
DistributionEastern Ecuador and Peru (the Rio Itaya at Iquitos)
Amazon, Upper Amazon, Marañón, Pastaza (click on these areas to find other species found there)
Show it on a map (Click the map-icon to show/hide map of species distribution)
pH5.8 - 7.0
Temperature24.0-26.0°C or 75.2-78.8°F (Show species within this range)
Other ParametersAppears to prefer a good but not strong water current.
Jump to next section Husbandry Information
FeedingWill eventually recognise and accept a variety of prepared foods, even flake, but is best acclimatized using frozen brineshrimp.
FurnitureHas a real affinity for wood. Much prefers to cram itself into dark places under bogwood than stone or plant.
CompatibilityA very peaceful fish, one of the most timid of the doradids.
Suggested TankmatesAs long as they are not too boisterous and preferably not nocturnal, this species will get on with most as it is active at night.
BreedingUnreported.
Jump to next section Further Information
ReferencesCopeia 1976 (no. 1), pp44, Figs. 1-2.
Registered Keepers(1) lazymf, (2) M.O.F., (3) Gulper.

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Last Update2013 Feb 10 16:05 (species record created: 2005 Sep 01 11:22)

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