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Spiny Eel Update!

I've written quite a few words on Spiny Eels (Family Mastacembelidae), most notably emphasising key issues such as the fact that these fishes are crepuscular (twylight active) and in the wild live as ambush predators striking from hiding places buried in the substrate. I've also mentioned that the majority of Spiny Eels are relatively hardy, with one principal exception, the Fire Eel Mastacembelus erythrotaenia) which has a well-deserved reputation for being more delicate than its relations, and that Spiny Eels appreciate subdued lighting, floating plants. and LOTS of hiding places. A deep substrate into which they can bury themselves without scratching themselves on sharp particles should be considered a 'must', as these fishes do bury themselves in the wild in preparation for ambush attacks, and if this is accompanied by complex bogwood tangles into which the fishes can wriggle and contort themselves around, so much the better. I've also mentioned in the past that aquarium companions should be chosen with care, as Spiny Eels WILL devour with relish any other fishes present that can fit into their mouths, and that the size of most Spiny Eels makes a large aquarium a must - 18 inches (46 cm approx.) is an 'average' size for members of the Genus Mastacembelus, while Mastacembelus erythrotaenia can attain a final body length of a metre - three utterly huge ones used to live in Liverpool Museum's basement aquarium section prior to the museum's refit, and part of the reason that they attained their immense proportions was that their home was a whopping 1,000 gallons!

However, most of the species that might be termed 'popular' Spiny Eels (in the sense that they're the ones most likely to be encountered) are South East Asian in origin, come from rainforest stream biotopes, and therefore are most likely to be happiest in moderately soft, slightly acidic water of the kind familiar to those like myself who are primarily keepers of South American fishes. However, this is NOT the whole story!

One new import I've seen described recently is known for the moment as Caecomastacembelus sp. "Yellow". Thus far, no-one knows how large this fish will grow, because it is a recent import and a rarity at that. It is also absolutely sky-high desirable among specialist Spiny Eel keepers, because this is a brilliant, solid yellow Spiny Eel! I have before me as I type this a photograph of the fish, and it is almost as solid yellow as a marine Lemonpeel Angelfish, which for a freshwater fish is VERY unusual to say the least! Sadly, the brief article that covers this gem (which is likely to be obscenely expensive if encountered by anyone here on the Board for the moment) does not give details of its geographical origin, so this expensive purchase will be a daunting prospect to anyone other than a specialist for the time being.

One species for which I DO have geographical information is the rare and expensive Aethiomastacembelus ellipsifer. This is a native of Lake Tanganyika, and therefore needs the same kind of water as shell-dwelling Cichlids, a radical departure from the favoured water conditions of its South-East Asian cousins. I mentioned this briefly in a past article (in General Freshwater prior to the 'year zero' archiving operation ) on Sean Evans, a keeper of assorted oddballs profiled in a past edition of Practical Fishkeeping magazine, and again, this is a fish that is likely to enjoy subdued lighting and lots of cover, although in this case the cover will most likely be of the rocky kind. Sean keeps his in an aquarium whose other occupants include Altolamprologus calvus, Cyprichromis leptosoma, Synodontis multipunctatus, the shell-dweller Neolamprologus multifasciatus and Julidochromis sp. 'Gombi' - we can assume, given Sean's experience in raising a wildly diverse fish range, that these are likely to be compatible, although I would personally have balked at the prospect of putting a Spiny Eel in with shell-dwellers in case the shellies were small enough to be an expensive lunch for the Eel! However, be advised that this is not the only Tanganyikan Eel likely to appear in the future, although most of these will remain expensive and rare for the foreseeable future.

Meanwhile, I cannot leave a piece on Spiny Eels without dwelling on the infamous "Tyre Track Eel" identity question. My infamous TFH back numbers from the 1970s carried a letter asking about this, and the reply from the editors stated that no less than three species were sold as "Tyre Track Eels". Bearing in mind that these taxonomic names are 1970s vintage, and may have changed, a Google search on them may still prove useful - they are Mastacembelus armatus, Mastacembelus loennbergi and Mastacembelus zebrinus. Of these, the one whose body colouration most resembles a car tyre pattern is M. armatus, but all three may appear in a dealer's under the name of "Tyre Track Eel", so if you want one of these, arm yourself with LOTS of photographs so that you can determine the identity of your prospective purchase, not least because in the hunt for these fishes, you may find yourself buying specimens from different dealers, only to find that your prospective Spiny Eel breeding project has collapsed at first base because you have one individual of each species ... all of these can be expected to reach 18 inches at least, and possibly more, so a substantial aquarium is a must for long-term housing.

And remember, they are twylight active in the wild. Which means that acclimatising them to auarium life includes the introduction of mobile live foods after "lights out" when they are first acquired. Once the Spiny Eels learn to associate you, the aquarist, with food, they will venture out during daylight hours (particularly if the aquarist has thoughtfully provided lots of cover, shade and suitably subdued lighting), and big ones can become real pets that will learn to take food from the aquarist's fingers. Fire Eels, despite their delicacy (most authorities agree that Fire Eels will only eat living foods in captivity), can become tame enough to stroke when large!

One final note from one of the Tetra experts with respect to Fire Eels - out of all the Spiny Eels, this is the one that is most susceptible to attacks by skin parasites. While other Spiny Eels may be subject to various assaults of this kind by unwelcome pathogens, the Fire Eel seems to be particularly poorly equipped to deal with skin parasites. Hygeine considerations are therefore very high on the list for keepers of Fire Eels. Also, Fire Eels are unusual in that they are sometimes found in brackish estuarine waters, and some aquarists have reported considerable success in keeping Fire Eels in brackish conditions, which also seems to aid them in fending off unwanted skin parasites. It is entirely possible that Fire Eels in the wild migrate to brackish waters naturally to 'convalesce', as it were, although confirmation of this would require the kind of scientific expedition I'd love to be able to afford but currently can't! Most of the other commonly available Spiny Eels, including the mish-mash of "Tyre-Track" Eels, are much less fussy about their conditions, and likely to prove considerably more robust in captivity, making them the Spiny Eels of choice for the aquarist venturing into this Family for the first time.

Meanwhile, if there is anyone on this Board rich enough to afford one of those solid yellow Spiny Eels (which are, at the moment, the fish world's equivalent of a Lamborghini - sky-high desirable and astronomically expensive) I'm sure Adam would appreciate you buying him a second server for the Board




Panda Catfish fan and keeper/breeder since Christmas 2002

Update:

Here's Sean Evan's Tanganyikan Spiny Eel ...

http://www.thetropicaltank.co.uk/Tanks/mytank9.htm

Enjoy!

Panda Catfish fan and keeper/breeder since Christmas 2002