I'm interested and can write reviews from the perspective of someone new to the hobby. I'm only 3-4 months in, but hopefully I can help someone that's...
I simply had a question (please forgive if this is not allowed, I read the FAQ but I was not sure). I was wondering if there is any evidence of offsp...
The sale of five invasive, non-native aquatic plant species is to be banned in the UK in order to protect wildlife and save money, the government has announced. Continue reading »
Members of the genus Cyprinodon, often referred to collectively as ‘pupfishes’, aren’t particularly well-known in the aquarium hobby for a variety of reasons, not least that many of the 50 or so species inhabit isolated environments and are not especially easy to maintain in captivity, plus they tend to lack the gaudy colouration which has made African relatives such as Nothobranchius or Aphyosemion so popular. Continue reading »
This is the “Foreword” to a planned series of short articles which are going to deal with different aspects of setting up and maintaining an aquarium. Continue reading »
Among the numerous disagreeable ways in which fishes are able to inflict pain and suffering on humans, from the sting of a Corydoras spine to the bite of a white shark, there exists one of which the mere notion has been causing eyes to water for over two hundred years.
The legendary catfish known by the names candiru in Portugese, cañeros in Spanish or wonderfully crude ‘willy fish’ in English has been viewed as a voracious destroyer of manhood since the 19th century when European explorers first returned from the Amazon region with horror stories about a fish with the ability to enter a person’s urethra as he or she relieved themself in the river.
Once there the creature would lodge itself in place using its opercular spines thus making it impossible to remove without considerable force, with the use of pliers, bladder or penis surgery, or amputation of the entire member among the more disturbing ‘remedies’.
The fish has been rumoured to enter the rectum, vagina, or even open wounds, but it’s supposed predilection for the male genitalia has generated by far the greatest horror and fascination.
Indeed, as one author remarked, treatment ‘requires the skills of a physician or, if the man is in a rainforest far from a physician, a machete and a very strong will to live’.
It was said to lurk invisibly in the water until the taste of human urine was detected at which point it would make a bee-line for the source before ‘ascending the length of the liquid column’ and entering the penis itself where it would lay ‘millions of eggs that hatch and devour the bladder’, ‘eat away mucous membranes and tissues until haemorrhage kills the host’ or simply gorge itself on blood.
It’s legend has been furthered by grisly references in contemporary literature from William Burrows’ ‘Naked Lunch’ and ‘The Yage Letters’ to mainstream media including BBC documentaries and the series ‘River Monsters’, and in recent years by the kind of internet sites which tend to promote the cruder varieties of sensationalism.
However, a review of candiru literature by Irmgard Bauer to be published in an upcoming issue of ‘The Journal of Travel Medicine’ suggests the truth to be rather less gruesome, and it appears that tightly-fitting undergarments may no longer be considered quite such an essential item in the backpacks of future Amazon travelers.
The paper begins with a review of internet and other media stories such as those mentioned above before discussing historic tales, and it quickly becomes apparent that much, if not all, of the folklore surrounding it is based on hearsay and repetition of the same accounts by various authors.
References are also made to the likelihood of misinterpretation during exchanges between native tribes and early Amazon explorers, and in translations of accounts from languages such as German, Portugese and French into English.
Other theories presented include the likely exaggeration of candiru rumours by enthusiastic adventurers, or use of the myth by natives in order to dissuade further exploration of their lands.
It’s also made clear that the great explorers of the time such as van Humboldt, Wallace and Bates did not mention the frightful fish at all.
Drawing of Vandellia spp. from Cuvier & Valenciennes 1846.
Other problems exist in determining what exactly constitutes a candiru. The name has been applied to a number of species belonging to the catfish family Trichomycteridae, a large grouping restricted to neotropical Central and South America.
Very few of them feed on blood with most having a relatively ordinary, benthic lifestyle, preying on aquatic invertebrates and suchlike.
The most notorious ‘bloodsucking’ species is undoubtedly Vandellia cirrhosa, a member of a small genus containing just three recognised species. It’s a parasite of larger fishes and is thought to be an obligate hematophage, meaning it feeds exclusively on blood, and tends to anchor itself within the gills of its hosts in order to do so.
Although theoretically small enough to fit inside a human urethra and despite being included in the genus Urinophilus (literally ‘lover of urine’) for a number of years, there exists no proof of it being attracted by urine and not a single record of an attack on humans.
Aside from the physical hardship involved in a fish successfully ascending a stream of urine (consider that for a moment) there is the question of what it’s supposed to do once it arrives at its ‘target’.
Wedged inside the urinal tract with no room to move further, no water to keep it alive and deprived of oxygen, it’s difficult to believe it could survive more than a few minutes and surely impossible that it could remain ensconced long term or lay eggs there.
In addition, there exist no modern records of a candiru being extracted from the body of a human with the exception of one contradictory report from Brazil in 1997, nor does it appear in the majority of current scientific databases or medical records.
Ony two such references are mentioned in the paper, the first from a survival textbook which recommends treatment with Huito fruit (Genito americana) as per historical texts, the idea being that acids in the fruit dissolve the invader’s skeleton. Application is by drinking a tea made from the fruit or inserting pieces in an unspecified location!
The second was taken from the ‘Lonely Planet’ guide to healthy travel where it’s suggested to ‘cover genitalia’.
In much of the available literature candiru attacks are referred to in such a way that they appear to be a regular, even common occurrence, whereas according to this latest review there exists no substantiated evidence that they happen at all.
The dwarf chain loach or ‘sid’, formerly Yasuhikotakia sidthimunki, has been assigned to a new genus in one of a number of important alterations to loach taxonomy published in the latest supplement issue of ‘The Raffles Bulletin of Zoology’. Continue reading »
Two new, closely-related species of zooplanktivorous haplochromine cichlid from southern Lake Victoria, Tanzania have been described in the journal ‘Zookeys’.
In the first of what we hope will become a regular interview series, we catch up with Malawi cichlid expert, ichthyologist, aquarist and webmaster Michael K. Oliver.
Michael has a long-standing interest in the cichlids of Malawi and both his Masters and Ph.D. research concerned the systematics of African cichlids.
He’s made a number of trips to the lake, diving alongside the fish and collecting specimens for scientific research, and has described some notable species including the rusty cichlid, Iodotropheus sprengerae, and sulphur-headed hap, Otopharynx lithobates.
Since 1997 he’s also been running The Cichlid Fishes of Lake Malawi, Africa, an incomparably comprehensive, open access resource for anyone interested in the lake and its species.
SF: Michael, you’ve been studying the cichlids of Malawi for almost five decades. How did you become interested in these fishes, and how has your passion been maintained?
MKO: Great questions, but they don’t have short answers. Well, first came a general interest in fish, by the time I was ten or twelve. I’ve thought a lot about how that happened – because, why would it? I grew up in Los Angeles, but not near the ocean.
My earliest memories involving fish are of a small aquarium in the office of my childhood pediatrician, and of several family visits to Marineland of the Pacific, an oceanarium (now long gone) with a giant ocean tank, smaller aquariums with fishes from various habitats, performing dolphins and seals – all the usual trappings.
Staring up at the jacks and sharks and bright orange Garibaldis swimming around the huge tank must have made quite an impression on my sub-teen self.
At 14 I got my first aquarium and soon started collecting books about fishes, including scientific books. I joined the Los Angeles Aquarium Society and became active in it, and haunted the local fish stores every few days (sound familiar so far?).
By age 16, I knew I wanted to become a fish taxonomist. I became aware of Malawi cichlids during these teen years. In about 1966 I saw a couple of colorful species of mbuna at my local fish store (US$40 each, I think), and also remember reading an article about them in TFH.
My mother and I traveled quite a bit with my father, a college English professor, during his sabbatical leaves every few years. When I was 17 we were planning a trip that included traveling through Africa from south to north. I successfully lobbied my dad to let me arrange a stop in Malawi; I wanted to see those colorful cichlids in the wild.
I wrote to the Chief Fisheries Officer of Malawi (an actual paper letter in an airmailed envelope – this was the 1960s). It was forwarded to the Senior Fishery Research Officer, Mr. David Eccles, in Monkey Bay. Eccles invited us to visit him there and promised to introduce me to the local fishes.
Talk about a dream come true! David, an excellent naturalist, was a wonderful host during the couple of days my parents and I stayed in Monkey Bay. He organized collecting trips to the rocky shores of Thumbi Island East, and seining on the local sandy beach. We caught dozens of cichlids of many species, as well as cyprinids, catfishes, and even Aplocheilichthys johnstoni. I was like a kid in a … cichlid store.
The sheer diversity of the cichlids was stunning (and only a couple of hundred species were known then). Seeing many of those 40-dollar cichlids at one time, glowing with color, fresh from their rocky habitat, also made an impression. Those two days with Eccles focused my future studies specifically on Malawi cichlids.
Incidentally, he and I collected specimens of a pretty little rocky shore cichlid with three spots. David wasn’t sure what it was, and my continuing efforts to identify it back in Los Angeles and at the British Museum eventually showed conclusively that it was undescribed. Years later I described it under the name Otopharynx lithobates, and it has justly become a favorite in the aquarium.
With that 1968 visit, I think I was the first American to visit Lake Malawi because of its fishes since the 1929 American Museum of Natural History collectors, R. and L. Boulton, caught a few fishes at Karonga and Deep Bay. I had taken lots of photos, and after returning home I wrote a three-part illustrated article for The Aquarium magazine about my visit to the lake, published in 1970.
At the time, only mbuna were exported to the aquarium trade; my article emphasized that there were a lot of colorful non-mbuna cichlids that would be very suitable for the aquarium.
When I later met Peter and Henny Davies, the first exporters, in Malawi in 1971, they told me that my article had persuaded them to begin exporting non-mbuna “haps,” which did indeed become very popular.
As for how I maintain my interest – how could it be turned off, once started? I think E. O. Wilson’s idea of biophilia – an “urge to affiliate with other forms of life” – has merit, but I believe that some people also feel a more specific attraction to biodiversity.
Certainly I do; in addition to my cichlid interests, I collect beetles, which make cichlids look depauperate!
SF: How complete is the taxonomy of cichlids from the lake? Do you think there are still new discoveries to be made?
MKO: Oh, certainly there are many species still to be discovered. About 400 cichlid species have been described to date from Lake Malawi.
Between 450 and 500 additional suspected species have been collected, photographed underwater, or both, but remain undescribed. Just about any visit to a remote rocky shore produces further new discoveries, as do deep-water trawls in unsampled areas.
If recent experience with other fish groups is any indication, there are also likely to be some cryptic species discovered among what we now regard as a single morphologically defined species.
Beyond just recognizing and naming all the species, most of the details of their phylogenetic interrelationships are still unclear; when better understood, this is sure to cause extensive revision of their generic classification.
SF: You recently described a new species which is interesting in a number of ways. Can you tell us about it?
MKO:Hemitaeniochromis brachyrhynchus is the second species of its genus to be described. Compared to the much better known H. urotaenia, the recently named form is anatomically odd.
The head appears scrunched up in front of the eyes because the superficial bone (the lacrimal) between the eye and the upper jaw is extremely narrow, giving the fish an unusually short snout (brachyrhynchus means short snout). The eyes are also unusually large.
Circumstantial evidence strongly suggests that H. brachyrhynchus is a paedophage – one of the cichlids that steal and eat eggs or fry being brooded in the mother’s mouth.
But, only two specimens are known; even the life coloration is a mystery. (The description was published as an open-access paper, so if interested to learn more about this cichlid you can freely download it from http://www.mapress.com/zootaxa/2012/f/zt03410p050.pdf.)
SF: Are wild Malawi fish still collected for the aquarium trade and does this practice have any detrimental effect on natural populations?
MKO: Yes, there is at least the large enterprise founded by the late Stuart Grant (see http://lakemalawi.com) at Kambiri Point near Salima, Malawi.
The most significant damage to natural populations by aquarium collectors was probably the intentional transplantation of cichlids between different parts of the lake by the Davies some 40 years ago, simply for their own convenience (for instance, taking Likoma Island endemic cichlids and releasing them at Thumbi Island West, over 200 km away).
This selfish, reprehensible action allowed hybridization and competition between species that would never have encountered each other naturally, and further complicated attempts to understand the already extremely complex natural distribution patterns of the cichlid species.
I’m not aware of any instance where overcollecting for the aquarium trade has seriously threatened a cichlid population in Lake Malawi, but given the small size of the populations of some species, an irresponsible collecting operation could definitely reduce a population (and even some entire species) to a level where it could not sustain itself.
SF: Do you think that the speciation of Lake Malawi cichlids will ever stop, and is it possible that some extant species may disappear naturally as a result of the ongoing speciation process?
MKO: As long as there are cichlids in Lake Malawi, they will continue to differentiate and speciate, facilitated no doubt by continued fluctuations in lake level which isolate and reconnect stretches of rocky shore, and by other factors such as changes in female preference for male coloration.
Extinction is also a natural process. Many species have surely arisen only to disappear within the lake, and more will do so.
I like to imagine that, a few tens of millions of years from now, as the two tectonic plates between which Lake Malawi lies continue to pull apart – the Rovuma plate on the east, the main Nubian plate on the west – the lake will become connected to the southern Indian Ocean and some future cichlids will adapt and invade the coral reefs.
SF: What do you see as the biggest challenge(s) facing the lake in the future?
MKO: Unfortunately, I think there are several.
1) Continued commercial overfishing in the south (ring-netting, trawling) has already probably driven some cichlid species to extinction and others to its brink. Artisanal fishing by the lakeshore villagers has also become a significant threat in some areas; very long and fine-meshed nets that catch even juvenile cichlids in large numbers are now widely used. See video:
2) Siltation from agricultural runoff into the lake is occurring, notably in the southwest near Salima.
3) Chemical pollution from agriculture could also increase, its effects aggravated by the long turnover time of the lake with its single outflow, the Shire River.
4) Oil spills from planned drilling in the north are a potential concern.
SF: What do you consider the most important items to pack when on a Malawi field trip?
MKO: I’m afraid it’s been a long time since I was there. Some obvious suggestions: For fishwatching, snorkel and mask (fitted with prescription lenses, if needed); a neoprene vest; for SCUBA: your second-stage regulator, dive computer, c-card, dive log, maybe a camera; extra batteries (perhaps rechargeable, with charger) and extra digital storage media.
The friendly and helpful local people always appreciate a few inexpensive gifts such as wristwatches and tee-shirts.
MKO: Both, of course! Keeping to Lake Malawi, grilled tilapia fresh from the lake are hard to beat, but smoked mcheni (Rhamphochromis) are also delicious, if rather bony. Even dried usipa (Engraulicypris sardella) are interesting to taste – once (it probably helps if you like the taste of gallbladder…).
SF: Mmmm, gallbladder! Michael, it’s been a great pleasure having you take part in our first ever SF interview. Thank you very much and all the best for 2013!
MKO: Thank you so much for the honor of being your first interviewee! It has been an entirely positive experience.
Product reviewers wanted
Hello! Very much interested in writing for you, please include me in the info. Thank you for the opportunity!
6th Sep 2020
Product reviewers wanted
I would be interested in reviewing products. Before retiring I was a technical writer and managed a Quality Management Program.
30th Aug 2020
Product reviewers wanted
I'm interested and can write reviews from the perspective of someone new to the hobby. I'm only 3-4 months in, but hopefully I can help someone that's...
23rd Aug 2020
Product reviewers wanted
I’m interested in doing this if there is still availability, it sounds like fun! Thanks
19th Aug 2020
Barbodes semifasciolatus – Golden Barb* (Barbus sachsii, Puntius schuberti)
I simply had a question (please forgive if this is not allowed, I read the FAQ but I was not sure). I was wondering if there is any evidence of offsp...
12th Aug 2020