Eyeball On Oddballs: The Fiery Fire

Derek P.S. Tustin

Every once in a while, we as aquarists get “caught in a rut”. Sometimes, we don’t stop and look outside our own In reading on this , it appears that it demonstrates a specific area of interest to discover some of the other very interactive nature with its owner. They apparently wonderful creatures that are available to us in this hobby. can become quite tame, willing to take food from the After the September 2007 DRAS General Meeting, I owner’s hand, and sometimes actually twining around the asked the editor of Tank Talk, Ivan Shaw, what he hand that feeds it. In the wild they are a predator and can thought I should do an article on. After thinking for be found in all water levels. In the aquarium, they will several seconds he responded – “Fire ”. It was likely spend most of the time either buried in the substrate somewhat appropriate as one of our members purchased or tucked in a crevice. Being nocturnal, they tend to be one at the June 2007 DRAS General Meeting auction. more mobile at night. They are relatively peaceful and are So off I went to my trusty computer and started doing especially so at a young age. If introduced while still research. And I must admit, I’m ashamed I never took a small, they apparently will not hunt smaller tank mates that closer look at this creature before this. were in the tank prior to their arrival, but as they grow, will go after any newly introduced smaller fish. Known for a quite some time in the hobby (first being described by Bleeker in 1850), the fire eel Fire eels are also escape artists and are able to jump quite ( erythrotaenia) is first off not a true eel. high. Therefore care must be taken to ensure that Rather, it is an elongated, tropical freshwater fish openings from the tank are well covered. (On a side note originating in streams of Southeast Asia. This area – my award for best writing on the internet in relation to includes Borneo, India, Malaysia, Myanmar, Sri Lanka, the fire eel goes to whoever wrote this: “You will need a Sumatra, and Thailand. It has a very distinctive pointed good, completely covered top to ensure the Fire Eel does snout, an under-slung mouth, and numerous spines not accidentally try to migrate out of the aquarium.”) preceding the . The body itself is laterally Anything its own size or larger are apparently good tank compressed, especially in the rear third where it flattens mates for the fire eel. While you are able to keep more as the body joins the caudal fin. This results in an than one while they are juveniles, there should only be extended tail, and the resemblance to a true eel. The one fire eel in a tank when mature (unless you are trying body colouring is either a dark brown or grey (appearing to breed and then it should be a 1:1 ratio of male to to be black in some specimens) with the belly being a female). They grow very quickly and, in the wild, can grow lighter shade of the same base colour. There are usually from 15 centimeters (6 inches) to over 1 meter (3 feet) in several bright red lateral stripes and spots marking the under a year. However, they usually will not grow to more body. These markings vary in intensity depending on the than 50 cm (20”) when kept in captivity. age and condition of the fire eel. Some websites suggest that there may be a mixture of yellow/orange lateral Also, you should be careful with heaters in a tank stripes along with the red ones, but it appears that containing fire eels. As they tend to twine around objects, juvenile fish will have yellow/orange markings that will they can do significant damage to themselves should they deepen to the deep red in more mature specimens. In decide to cuddle with the heater. A heater guard in a tank most but not all specimens, the anal, pectoral and dorsal with a fire eel is definitely a good idea. Other health fins will have a red edging. It appears that both the fin issues that are common with fire eels is that they appear and body markings will lessen in intensity if the fish is to be more prone to parasite attacks and shock.

kept in sub-optimal conditions. (continued on page 16)

The fire eels’ natural habitat is slow moving waters flowing over soft riverbeds, and it is recommended that in captivity you try and mimic the natural conditions. The substrate should contain both sand and round-edged stones. A sand substrate is especially important for this fish as it will spend a large portion of time buried in it, often only with its snout protruding. Decorations should include aquarium wood and rocks placed in such a way that there will be numerous crevices and caves for sanctuary. Finally, the aquarium should be densely planted with additional floating plants. The floating plants will lessen the light penetrating into the tank and make the fire eel, which is essentially a nocturnal fish, more comfortable. However, you should note that due to their burrowing nature, there is the chance that they will uproot plants and move driftwood as they find a comfortable hiding spot. Fire Eel (Mastacembelus erythrotaenia)- Photo by Steven Rasmussen

Tank Talk – October 2007 12 Volume 35, Number 2

Eyeballs On Oddballs: The Fiery Fire Eel Showing Fish (continued from page 12) Kevin Omura

Fire eels are reported to be omnivorous, but especially I actually don't think there is a real secret to doing this, the like bloodworms, live black worms, and brine shrimp. main thing is to just go out and do it! The monthly jar show However, as they tend to remain at the bottom of the is a great way to test the waters so to speak, your fish aquarium, you must take steps to ensure that the fire eel aren't going to be out of the tank for very long so there receives food and is not out-competed as other fish eat won't be as much stress on your prize fish then if you were the food floating to the bottom. If you see the fire eel showing at some of the bigger venues. grazing on soft-leaved aquarium plants, this may be an indication that it has not received sufficient food in the What to show? Well I realized I have a 'bad' eye when it preceding days. comes to detail so I let Annette pick for me but mainly you are looking for perfect fins, no signs of disease and good The fire eel is reportedly very difficult to breed. It has body form. Sick fish are automatically disqualified. I was only been reported with mature fish (over 50 cm or 20” in from the school of bigger is better but actually that isn't size), but is a very rare occurrence. They are plant always the case the main thing is to pick the perfect fish. It spawners, laying 800-1200 eggs in floating plants. The also takes some planning and strategy, this year for eggs are clear and measure about 1 mm in size. It is example I setup a 100 gallon tub in the backyard and filled reported that the best water parameters for breeding are it with livebearers which I bought at a club auction. Grew a pH around 7.0, water hardness from 10-15 dH (179 – them out all summer so I would have entries this fall. For 268.5 GH), and a temperature ranging from 27-29°C (81- the monthly special I might pick up possible candidates a 84°F). Sexing fire eels is also extremely difficult, few months ahead of time and grow them out. It kind of although the female tends to be plumper than the male. makes for an interesting mix of fish in our fishroom and Should you succeed in actually breeding them, you must we've wound up with some nice fish that I might not have be very careful with the fry. The young will also grow normally considered. quickly, and will gorge themselves on whatever food is offered, and if the fry do over-eat, they will likely die. How to show? This is fairly straight forward, any flat sided container will do so we are talking about flat sided goldfish With the numerous special conditions that must be bowls, beanie cubes, small rectangular fish tanks or the observed when keeping a fire eel, it is easy to see that small insect containers you can pick up at Dollarama. The this is not a fish for beginners. However, if you are able latter is what I use for our smaller entries. They can be to meet all requirements, the fire eel is a beautiful and easily floated when I get back from the jar show before interactive addition to your tank. releasing the fish back into their respective tanks. Also read the rules carefully as they may vary depending on the club Species Profile or association. Some allow backgrounds and some do not. Rules for the jar show are posted on the DRAS website as Latin Name: Mastacembelus erythrotaenia well as in Tank Talk. Common Name: Fire Eel Size: 55 cm (22”) – in captivity Does it take a lot of work? Well yes, I actually take the day Temperature: 24-27°C (75-81°F) off the day of our meetings. It normally takes me a good pH: 6.0-7.5 couple of hours or more to prepare for the show. Normally I GH: 107.4 – 358 (a little salt is recommended) try and show three fish in each category although KH: 8 – 20 sometimes I might enter an extra one in one or another Diet: bloodworms, live black worms, brine shrimp Distribution: Southeast Asia – India to Indonesia class if I don't think I have strong fish in the special category. I try and pick my entries just prior to leaving so that our fish don't spend too much time in their small containers. I normally have a mix of 50% tankwater and 50% new water in each jar prior to adding fish. We keep our most of the tanks in our fishroom at room temperature which hovers around 72-76 degrees so when I get back from the meeting I place each jar in front of their respective tank and wait a few minutes until the fish are up to temperature. I had been thinking of putting stick on thermometers on every jar so that I have a better idea of their temperatures.

In the spring of the following year all the jar show winners, 1st, 2nd, and 3rd place receive a plaque or certificate which looks great on the fishroom wall at the annual awards banquet. There is a great dinner, guest speaker and with some luck you might even get a behind the scenes look at the fishrooms at the Toronto Zoo! Fire Eel (Mastacembelus erythrotaenia)- Photo by Steven Rasmussen

Tank Talk – October 2007 16 Volume 35, Number 2