Misgurnus anguillicaudatus - Dojo loach (weather loach)
An article by Carli Flenniken
While the Dojo loach (Misgurnus anguillicaudatus, aka weather loach, Japanese weather fish, Amur weather fish) may not be the flashiest loach you may have seen in aquaria, it is easily one of the most interesting. This loach is native to China, parts of Siberia, Korea, Hainan and Japan. In Japan, they are considered a food source…apparently they are quite nutritious having “200 times more calcium than eel” as one Japanese site proclaimed. Out of curiosity, I searched for recipes, and it seems the preparation of choice is in the form of stew and soup (dojo nabe and dojo udon).
Of course, I’m much more interested in the keeping of this lovely fish than I am in the preparation of, though I now look to see the Dojo as the main ingredient in a forthcoming Iron Chef episode. And as attached as I am to my own Dojo, I am, quite frankly, emotionally scarred.
What was upsetting to me was when I discovered that certain areas of Hawaii had become so overrun with Dojos that had been released by hobbyists, that these poor unfortunate creatures are now being used for bait rather than swimming through the waters to an inspirational round of Born Free. Moral of the story, don’t set non-indigenous fish free!! Now that I am off my soapbox, back to the issue at hand.
The Dojo may not have the color of the clown loach or Botia modesta (both of which I keep as well), but he is interesting looking in his own right. Long and eel-like, in the wild they can reach as large as 25 cm (one report said 50 cm!!), capable of reproduction at 10-15 cm. In an aquarium environment, they tend to not exceed 15 cm. Mojo (my own Dojo) is approximately 12.5 cm, and is at least two years old. His predecessors (a pair I kept in my tanks for several years) reached at least 15 cm, if not a bit larger before they passed away within weeks of each other. Their coloration tends to be brown to grayish, and mottled with darker spots. They have, of course, the “loach face” I am personally so fond of, with fleshy rounded mouths with 5 pairs of barbels surrounding it.
Reproduction is problematic, and it seems there are no accounts of actual hatchings (that I could manage to dig up, anyway) in captivity, though there have been reports of eggs scattering. Dojo eggs are adhesive, tiny and red, and it is said, amazingly, that the number of eggs per clutch can range from 1,800 to over 15,500. Ideally, they can be sexed by the pectoral fins. Mature males should have a thicker and longer second ray than the females, giving the pectoral fins a triangular rather than round shape. In my pictures, you can see the point made by this ray.
They are omnivorous, with a preference for meat. I feed brine shrimp, bloodworms, mosquito larvae, shrimp pellets, flakes, algae tablets and peas, and nothing is ever turned down. They also make up part of a wonderful clean up crew, scavenging through the gravel to pick out anything that may have been overlooked by the other tank mates.
Dojos are possibly the easiest fish I have ever kept. If he is fed and has room to play, he is a happy loach. In the wild, these loaches are found in cool, shallow, still waters. They survive harsh winters by burrowing into the substrate, and can be seen burying themselves this way in the aquarium. They can also survive long periods in very shallow water, and even out of water, as well, because of their ability to produce a protective slime coat, gulp air much like corydoras and plecos and can absorb atmospheric air through, believe it or not, their anus.
Dojos can tolerate very low as well as very high temperatures, and seem to thrive in temperatures ranging anywhere from 4-25 degrees Celsius, and do well in ponds, unheated tanks, and tropical tanks alike. In my opinion, a tank of at least 30-gallon capacity is a must. Although Dojos don’t normally get very large in captivity, they are very active and playful. When kept in too small quarters, they are likely to hurt themselves, as I found out when I originally had my pair as juveniles in a 10-gallon tank. One jumped high enough to hit the top, and managed to do it hard enough that I thought he had killed himself. Luckily he regained his senses a few moments later, after laying on his back in the gravel for a several seconds (which felt like much longer) in an incredibly alarming manner. They also can tolerate almost any pH, though 6.5-7.5 would be optimal. A sand substrate is recommended, because of their habit of burrowing and digging. Dojos also need places to hide, although they are active fish, they tend to be more active in the evening and night, normally preferring to rest in seclusion during the day.
Dojos are not aggressive, and ideal tank mates would be any fish that won’t hurt them. Personally, I would also suggest not keeping them with fish that are too easily spooked, as you never know when they will go on a frantic dart about the tank, an activity which a Dojo can amuse himself with for hours. Mojo has been kept with leopard danios, a pair of angelfish and a rather motley and hyper collection of botias, and “socializes” with all the other loaches indiscriminately. He often takes part in the “loach pile” the clowns are so famous for, or can be seen curled up sharing a cave space with a modesta. He does like to “tease” the other fish, and sometimes chases, but never fights or hurts the other fish.
There are even more oddities associated with this particular loach than those already mentioned. First and foremost is the reason for the name “weather loach”. Dojos have been dubbed as such because of their sensitivity to barometric pressure, which causes them to become restless before bad weather. These particular pictures were taken the evening before a rather violent morning storm, and Mojo was frantically darting about the top regions of the tank, and area he is rarely seen in. It seems he discovered a new game when he realized he could swim into the front of the filter and ride the wave from the outpour. He spent the entire evening and the next day circling around the back of the filter to the side, riding the water down, then circling back around the back to do it again.
Another oddity that makes this fish so loveable is that they don’t seem to mind being touched, sometimes even seeking out the contact themselves, and hand feed quite easily. Every Dojo I have ever had has seemed to enjoy this sort of attention, and I have seen other hobbyists comment on this same behavior as well. Most discover this tendency when they stick their hand in the tank and all of a sudden find a Dojo sliding against their hand or through their fingers. They are kind of like cats though; they have to be “in the mood”. When they aren’t, you can spend three days trying to net them just like any other fish.
Their hardiness makes them perfect beginner fish. Their gentle temperament makes them ideal tank mates. Their personality is endearing to anyone who wishes to have a more “pet like” species in their tanks. All in all, Dojo loaches are a perfect addition to almost any community tank.
Photos and text by Carli Flenniken