Forget watching the news, the dojo loach will let you know when it’s going to rain instead! These fascinating fish are one of the most common loach species to come across in aquarium stores and have some of the most interesting behaviors and personalities. While easier to keep than other species, they are generally categorized as coldwater fish and will not be able to be kept with other tropical fish.
Keep reading to find out everything you need to know about dojo loach care and keeping one of these freshwater fish in your own aquarium!
Misgurnus anguillicaudatus is commonly known as the dojo loach, pond loach, oriental weather loach, and the oriental weatherfish. ‘Dojo’ comes from the Japanese word for loach. More interestingly, the oriental weather loach was given its other common name because it is believed that shifts in barometric pressure cause the fish to demonstrate more frantic swimming patterns. Changes in barometric pressure usually indicate precipitation in the near future, making these fish a natural meteorologist!
The Misgurnus genus is still poorly documented and understudied, and the exact number of species is not reported; most discovered species have been located throughout China and Russia. However, as a member of the Cobitidae family, Misgurnus anguillicaudatus is recognized as a true loach along with about 260 other species.
Release, hybrids, and other uses
Dojo loaches have become a major invasive species across most parts of the United States, Canada, Australia, Europe, and Asia. It is believed that aquarium release, aquaculture, and use as a popular baitfish has caused dojo loaches to impact many natural ecosystems and their resulting food chains.
The dojo loach has been subject to hybridization for research purposes as well as by natural means. M. mizolepis and Paramisgurnus dabryanus are two of the main species that have been known to breed with Misgurnus anguillicaudatus. Otherwise, these fish are appreciated for their medicinal value and as a main food source in several countries.
The dojo loach is native to the majority of eastern Asia, including Korea, China, Japan, and parts of Vietnam. These freshwater fish can be found in calm and shallow streams, rivers, and swamps. The substrate is usually covered in leaf litter or mud, which allows the loach to burrow and hide.
Their natural environments are heavily influenced by the seasons, with oxygen levels and water current varying at different times of the year. The dojo loach has evolved special intestines and skin to help intake atmospheric oxygen if dissolved oxygen levels are depleted in the water column. If this happens, you may see dojo loaches swimming to the surface of the water for air; at the same time, they are able to expel intestinal gases. Dojo loaches have also been known to survive temporary periods of time out of the water by staying burrowed in soft mud and silt.
The dojo loach is sometimes misidentified as other species of loach, however, they’re quite easy to distinguish if you know what you’re looking for! These eel-like fish come in a variety of colors but most often will be found in a sandy-tan variation with darker brown and black spots along their dorsal area; their underbelly will be a lighter white/cream color. They will also have very apparent barbels around their mouth.
One of the more desirable variations hobbyists look for is the commercially-bred gold variation. The overall stature of the gold dojo is the same but instead of a dark dorsal area, they are a beautiful yellow with orange hues. Both variations will get along in the tank as long as they are both dojo loaches!
Females are generally larger than males. However, males will have enlarged pectoral fins and will have horizontal patterns behind their dorsal fin when viewed from above.
How big do dojo loaches get?
The dojo loach can reach 12 inches (30.5 cm) long when fully grown. These fish can also live to be 10 years old, though this is under pristine tank and water conditions and it is much more likely for your dojo loach to live 5-8 years on average. If kept with other tropical fish that need a higher water temperature, expect your dojo loach to have a significantly shorter lifespan, only living 2-4 years. (This is highly not recommended!)
Dojo loach tank requirements
While easy to keep, dojo loaches do have some specific tank requirements of their own. While it is unlikely that your dojo loach will grow to its maximum size of 12 inches (30.5 cm), it is always better to have more space than not enough. The minimum tank size recommended for one dojo loach is 40 gallons (151.4 L), with a 55 gallon (208.2 L) aquarium being even better. Some hobbyists have had luck keeping their dojo loach in outdoor ponds, but be warned, these fish are incredible escape artists!
Even though these fish can withstand most extreme temperatures, they do best in a range between 58-77º F (14.4-25.0º C); the temperature should not fluctuate too much and should not drastically change throughout the course of the day as this will definitely stress the fish out regardless of its ability to adapt. Water pH will need to be maintained between 6.0-8.0 with soft to medium water hardness.
A soft and muddy substrate is required to allow your dojo loach to burrow; gravel and other coarse substrates may stress your fish out as it is not able to hide and display its natural behaviors. Plenty of plants and smoothed rocks and driftwood should also be used to create additional hiding places. It is important to make sure that all aquarium decorations and plants are securely placed in the tank so that the dojo loach can’t knock anything over when digging.
Water movement should be minimal. While these fish can withstand areas of low dissolved oxygen, there should still be some water current throughout your aquarium, but not so much that the fish, substrate, and plants are being pushed around. Aquarium lighting should also be on the dimmer side, though dojo loaches can tolerate moderate lighting if desired plants require slightly higher intensities.
Dojo loaches will need some space between the surface of the water and the aquarium hood/lid so that there is room for them to breathe atmospheric air if need be. This also means that they are very likely to escape through small holes and other crevices you might have between the hood/lid and aquarium equipment; an open-top aquarium is definitely out of the picture!
Some hobbyists have even had their dojo loach escape, only to make a full recovery once being put back into the tank due to their ability to temporarily survive out of water. If this does happen to you, gently place the fish back into the tank with the lights turned off. Dose some slime coat protector if you have it and wait for a few days.
Dojo loach tank mates
One of the most important things to consider when getting a dojo loach is that while they are peaceful fish that will get along with tropical fish, they will not thrive in the temperatures that those same fish require. Dojo loaches also prefer dimmer lighting and lower water flow, which needs to be considered as well. This can make stocking your dojo loach aquarium a little more difficult, however, that doesn’t mean that you can’t have other fish!
Good tank mates might be:
Goldfish (Carassius auratus). Yes, you read that right! Dojo loaches are one of the few fish species that can be kept with goldfish. As long as there is enough room for everyone (and enough filtration), then goldfish and dojo loaches should get along great! It is only recommended to attempt this if the aquarium is at least 55 gallons (208.2 L).
Zebra danios (Danio rerio). Another type of coldwater fish species, the zebra danio is a very active mid- and upper-water column swimmer and does best in water temperatures between 65-75° F (18-24° C). These black and silver striped fish only grow to about 2 inches long (5 cm) but will need to be kept in schools of at least 6 or more. Zebra danios are pretty hardy but will still need enough space to swim around and participate in schooling behaviors.
White cloud mountain minnow (Tanichthys albonubes). Similar (and closely related) to the zebra danio, the white cloud minnow will also do best when kept in lower water temperatures, specifically between 60-72° F (15-22° C). These fish only grow to about 1.5 inches (2.5 cm) and will also need to be kept in schools of at least 5 or more. They are pretty active swimmers given their smaller size and will bring life and excitement to the middle and upper portions of the tank.
Paradise fish (Macropodus opercularis). If you’re looking for a statement piece for your dojo loach tank, then the paradise fish will definitely do just that! These fish are a more ornate version of the gourami and will grow to be about 2-4 inches (5-10 cm). While these colorful fish are more aggressive than the previous tank mates listed, they tend to only go after smaller fish. They also have a similar preferred water temperature to that of the dojo loach.
Dojo loach (Misgurnus anguillicaudatus). Lastly, these fish like to be kept in groups and will do just fine if kept in a tank with just their own species! Some hobbyists claim that dojo loaches do best in groups of at least 3 while others say they prefer a more solitary life. While each fish is different, it seems that dojo loaches especially appreciate being close to other similar fish. Always make sure that the species you’re interested in match those water temperature requirements of the dojo loach and that enough space is allotted.
More aggressive fin-nippers should be avoided. Remember, never place tropical fish with your dojo fish as the species will be incompatible when it comes to preferred water temperatures.
Dojo loach behavior
Dojo loaches have very interesting personalities that will keep you guessing what they’ll do next! Naturally, these fish like to stay near the bottom in their hiding places where they can burrow into the substrate with just their eyes peeking through. However, in the aquarium setting, they tend to be a little more friendly and active in the forefront of the tank.
Because of this, they should not be kept with slower species of goldfish, like fancy types, as the goldfish may be outcompeted when it comes to feeding time. Some hobbyists have found that these fish tend to do better with their own species and other similar-looking fish; they quite literally like to cuddle up next to each other! While it is not necessary to keep more than one dojo loach in your tank, they tend to be more active and upfront in the tank when they’re among others.
Dojo loaches will also naturally venture to the top of the tank to breathe from time to time. This is no cause for concern as long as they’re not doing it too frequently. If you see your dojo loach going to the surface of the water to breathe more than a few times every day, it may be due to a lack of water movement in your tank. Better water surface agitation and gas exchange may be needed by using a powerhead or air stone.
Are dojo loaches aggressive?
While more dojo loaches are very peaceful and even playful towards other fish, some hobbyists have had problems with their fish being overly active and nipping at fins. For the most part though, as long as the tank size allows and water temperature requirements are met, then there should be little to no problems between coldwater species.
If your dojo loach does appear to be aggressive, try feeding more frequently and adding more hiding spots. If the tank is large enough, try adding more dojo loaches (but also be prepared to remove them if things aren’t working out!) in hopes that a group will help with the aggression.
Do dojo loaches eat other fish?
While it’s unlikely, dojo loaches have been known to go after smaller fish. Always make sure that your loach is getting enough food so that it doesn’t try to actively hunt in your tank.
Like most other bottom-dwellers, dojo loaches will also see dying/dead fish as food. This can make them a very good member of your clean up crew, but should never be used for just that purpose.
While dojo loaches are not likely to eat fish, they are definitely likely to go after small shrimp and snails. Loaches are notorious snail eaters, and the dojo is no different! If you really want to keep shrimp and snails in your tank, then make sure that they won’t be able to fit inside your dojo loaches’ mouth; also, don’t be upset if your fish ends up eating their new tank mate regardless!
While dojo loaches will eat small invertebrates, they usually don’t do so at a fast enough rate to control infestations. Remember, never purchase aquatic life in hopes of fixing a temporary problem unless you can house that animal indefinitely!
Dojo loach diet
Dojo loaches are mostly carnivores, meaning that survive primarily off of meaty food, like small insects, eggs, and other crustaceans. Despite their appetite for meatier foods, they don’t tend to be too picky when it comes to aquarium care.
What does a dojo loach eat?
For the most part, dojo loaches will eat whatever food passes by them in the water. Since they mainly stick to the bottom of the tank, it is important to make sure that any other freshwater fish in the tank aren’t eating all of the food before it makes its way down to your loach.
You should offer your dojo loach a variety of live, frozen, and dried foods, like worms (earthworms, bloodworms, etc.), brine shrimp, and other meaty foods. It is not uncommon to see your fish regularly scavenging around the bottom of your tank in between feedings.
If you’re having difficulty making sure that enough food is getting to the bottom of your tank, try target feeding your dojo loach by using a turkey baster; for larger and more solid foods, you can also use tongs.
Breeding dojo loaches
Not much is known about the breeding preferences of dojo loaches, and there has been little success in the aquarium trade. If wanting to try your hand at breeding this species, first make sure that your pair is of male and female. Water conditions will need to be as close to as pristine as possible and highly stable. Offer a variety of high-quality foods with plenty of hiding places throughout the tank.
If you happen to (luckily) notice eggs/fry, it would probably be best to remove them from the display tank and transfer them into a separate aquarium with identical conditions.
The dojo loach is the perfect bottom-dwelling species to add to your coldwater aquarium! They are one of the few fish that can be kept with goldfish, but also have the personality to be kept on their own. While they need a larger tank, having multiple Misgurnus anguillicaudatus will bring out their best! Plus, they will keep each other and yourself company for up to 10 years!
If you have any questions about dojo loach care or have kept these fish before in your own aquarium, don’t hesitate to leave a comment below!