The dojo loach, also known as the weather loach or pond loach, is a captivating freshwater fish native to East Asia. This species, scientifically classified as Misgurnus anguillicaudatus and part of the family Cobitidae, has become a popular choice among aquarists for many years.
Aquarists appreciate the dojo loach for its remarkable adaptability, peaceful temperament, and engaging behaviors. Known for their playful nature, these fish often burrow into the substrate and interact with their tank mates, adding a dynamic element to any aquarium. Their unpretentiousness makes them suitable for various tank setups, appealing to both beginners and seasoned aquarists.
Contents
Habitat in the wild
The dojo loach (Misgurnus anguillicaudatus), a member of the Cobitidae family, is commonly known as the weather loach. This species is primarily distributed across Eurasia, with a few populations in North Africa. Loaches are recognized for their elongated bodies, small scales, and distinctive barbels around their mouths.
Habitat and Distribution
The dojo loach is endemic to regions such as Siberia, Sakhalin Island, Korea, Japan, China, North Vietnam, and potentially Laos. Interestingly, it has successfully established populations in countries like Germany, Spain, Italy, Kazakhstan, Uzbekistan, Turkmenistan, the Philippines, the USA (including the Hawaiian Islands), Canada, and Australia. This wide distribution is largely attributed to the fish’s popularity in the aquarium trade, as well as its use as bait in fishing.
The dojo loach’s adaptability, omnivorous diet, high reproductive potential, and low vulnerability to predators have facilitated its spread. However, this expansion raises ecological concerns, as dojo loaches can displace native fish species in their new habitats. In some regions, like England, special permits are required to sell or keep this species due to its potential impact on local ecosystems.
Natural Habitats
You can typically find dojo loaches in shallow waters of streams and rivers, as well as in ponds, bogs, and other slow-flowing bodies of water. They thrive in densely planted areas with fallen leaves and prefer sandy or muddy substrates. In rivers, they favor muddy habitats rich in vegetation, often residing in distributaries, bays, and dead stream branches.
When oxygen levels are low, dojo loaches have a fascinating adaptation: they swim near the water’s surface, gasping for air and producing a characteristic squeak. This unique behavior is possible because dojo loaches can breathe not only through their gills but also through their skin and intestinal tract, thanks to a dense network of blood vessels in their gut walls. This allows them to survive in low-oxygen environments and even to dig into the mud to hibernate for extended periods until water returns.
During seasonal changes, dojo loaches can move into temporarily flooded areas and may survive dry spells in wet sand or mud. Fishermen have noted that larger species, along with eels, can sometimes travel between closely located ponds during dewy mornings.
Conclusion
The dojo loach is not only a resilient and adaptable species but also plays a significant role in its ecosystem. Its unique respiratory adaptations and behaviors make it a fascinating subject for aquarists and nature enthusiasts alike. Understanding the dojo loach’s characteristics and ecological impact can help in appreciating its place in both wild and aquarium environments.
Why weather loach?
One of the most fascinating features of the dojo loach is its remarkable sensitivity to atmospheric pressure and weather changes. This sensitivity manifests in distinct behaviors; for example, when a storm is approaching, the dojo loach often becomes restless, swimming erratically around the tank and even attempting to peek out of the water. Conversely, as atmospheric pressure rises, these loaches tend to become more sedentary, often burying themselves in the substrate or hiding in other areas of the aquarium.
This behavior is attributed to the dojo loach’s ability to detect fluctuations in barometric pressure, which is believed to affect their swim bladder. The changes in pressure trigger these unusual swimming patterns, leading to the nickname “Weather Loach.”
In various cultures, particularly in Japan, people have observed this unique trait and have kept dojo loaches as natural barometers for predicting weather changes. Their behavior has not only provided insights into daily weather shifts but has also been used to forecast natural disasters, such as tsunamis and earthquakes.
Description
Physical Characteristics of the Dojo Loach
The dojo loach features an elongated body covered in small, distinct scales. Its mouth is lined with 10 to 12 barbels, and the tail fin is rounded. Notably, the infraorbital spine is situated deep under the skin and is non-functional.
The dojo loach has small yellow or brown eyes, with color intensity varying based on its habitat. Its body is typically a light olive or greenish hue, adorned with numerous small spots. Additionally, there are white and golden varieties available in the aquarium trade.
Golden Dojo Loach
One popular variant is the golden dojo loach, often marketed as “golden dojo loach.” This variety is partially albino, displaying a pinkish body with a yellow tint and dark-colored eyes. The golden coloration adds a striking visual appeal to aquariums, allowing it to stand out against various substrates and decorations.
Size of the Dojo Loach
The dojo loach can reach an average length of 6 to 12 inches (15 to 30 cm). However, some individuals have been known to grow even larger, occasionally reaching lengths of 12 to 15 inches (30 to 38 cm) or more in rare cases. This size distinction is essential, especially when comparing the dojo loach to other tank species like the kuhli loach, which shares a similar body structure but has a much smaller size.
Lifespan of the Dojo Loach
The lifespan of the dojo loach largely depends on the water temperature of its environment. Preferring cooler waters, the dojo loach thrives best at temperatures lower than those typical for tropical fish. When maintained in ideal conditions, it can live for 10 to 15 years or even longer in captivity; some well-cared-for individuals have been known to exceed 15 years. Conversely, if kept in warmer water, their lifespan may be reduced to around 8 years.
| Characteristic | Description |
|---|---|
| Scientific Name | Misgurnus anguillicaudatus |
| Common Names | Dojo Loach, Weather Loach, Pond Loach, dojo eel |
| Family | Cobitidae |
| Native Range | East Asia (China, Japan, Korea, Taiwan) |
| Size | 6 to 12 inches (15 to 30 cm) in captivity |
| Lifespan | 10 to 15 years or longer in captivity |
| Body Shape | Elongated, eel-like |
| Coloration | Yellowish-brown or olive with darker patches, lighter underside |
| Fin Type | Fins are transparent and delicate |
| Temperament | Peaceful |
| Behavior | Nocturnal, bottom-dweller, burrows in substrate |
| Feeding Habits | Omnivorous, eats small invertebrates, insects, worms, and plants |
| Aquarium Size | Minimum 30 gallons (113 liters) |
| Water Temperature | 64°F to 75°F (18°C to 24°C) |
| pH Range | Neutral to slightly alkaline (around 7.0 to 8.0) |
| Water Hardness | Tolerant of a wide range, slightly soft to moderately hard |
| Tank Setup | Soft substrate (sand or fine gravel), hiding spots, plants |
| Compatibility | Peaceful community fish, avoid aggressive or fin-nipping species |
| Breeding Difficulty | Challenging, requires specific conditions and setup |
| Special Feature | Can breathe atmospheric oxygen with a labyrinth organ |
Difficulties in keeping
The dojo loach is one of the most undemanding freshwater fish, making it an ideal choice for beginners and those who may not have the time to dedicate to intensive tank maintenance. Its adaptability and peaceful nature make it a perfect addition to a community aquarium.
However, it’s essential to note that the dojo loach thrives best in cooler water. Maintaining an appropriate temperature is crucial for its health and longevity. Beginner aquarists should consider using a reliable cooling system or keeping the aquarium in a cooler location to ensure optimal conditions for this species.
Care and keeping in a tank
Tank decor
The dojo loach is relatively easy to care for, but it does require specific habitat conditions to thrive.
Substrate Requirements
Providing a soft, small-grained bottom substrate is crucial. Large stones with sharp edges can harm the loach’s delicate skin, leading to stress. The ideal substrate for these fish is fine sand, which allows them to dig and burrow comfortably.
Decorations and Shelter
Including large, smooth snags and stones, as well as various decorations, will enhance the dojo loach’s environment. The more hiding spots available, the better, as these fish enjoy exploring and feeling secure.
Lighting Considerations
Moderate lighting is recommended for the tank. Adding floating plants can help shade the bottom, mimicking the dojo loach’s natural habitat. You might also consider incorporating fallen leaves to create a more authentic environment.
Safety Measures
It’s important to ensure that filters have safety caps and that the tank is covered with a lid. Dojo loaches can be jumpy, particularly when first introduced to a new setup. If you find your loach on the floor, gently return it to the tank; there’s a good chance it will recover quickly.
Water parameters
pH Levels
Dojo loaches can tolerate a wide range of pH levels but prefer slightly alkaline to neutral conditions. Aim for a pH range of 7.0 to 8.0. It’s essential to avoid extreme fluctuations, as sudden changes can stress the fish and impact their health.
Water Hardness
These loaches are adaptable to various water hardness levels. A general hardness (GH) of 8 to 12 degrees and a carbonate hardness (KH) of 6 to 12 degrees are ideal. This range will help ensure a comfortable living environment.
Temperature
While dojo loaches can survive in temperatures ranging from 5°C to 25°C (41°F to 77°F), the recommended range is between 20°C to 23°C (68°F to 72°F). Keeping the water within this range is crucial, as higher temperatures can shorten their lifespan and increase susceptibility to infections.
Water Quality
Dojo loaches are sensitive to poor water quality, particularly elevated levels of ammonia and nitrites. Regular testing is necessary to maintain ammonia at 0 ppm and nitrites at 0 ppm, with nitrates ideally kept below 20 ppm. Consistent water changes and a reliable filtration system are essential for keeping these parameters stable.
Diet
Basic Diet
Dojo loaches are omnivorous and thrive on a diet that includes a mix of insect larvae, small crustaceans, and sinking pellets. High-quality commercial fish foods formulated for bottom-dwelling or omnivorous fish serve as a solid foundation. Look for sinking pellets or granules that are small enough for your dojo loaches to consume easily.
Supplementary Foods
In addition to their staple diet, it’s beneficial to include frozen or live foods such as daphnia, bloodworms, and other worms. This variety not only enhances their nutrition but also stimulates their natural foraging behavior.
Interaction and Bonding
Dojo loaches are known for their affectionate nature and can develop a bond with their owners. They often enjoy gentle interactions, such as being stroked or hand-fed. This connection can enhance your experience as an aquarist and create a more enriching environment for your fish.
Tank mates
The dojo loach is undemanding in terms of keeping in a tank; it is active and peaceful, but it may prey on juveniles or eat fish eggs. You can keep just one fish in a tank, but they feel more comfortable in a company of its kind.
Perfect tank mates are goldfish. They require the same tank water temperature, they aren’t rivals in terms of food and they swim in different water layers. Loaches eagerly eat food leftovers that goldfish leave, which decreases the level of ammonia and nitrates content in the tank.
You can select any fishes that dwell in upper and medium water layers as tank mates; at that, they shouldn’t be large and aggressive. If these fishes aren’t aggressive towards dojo loach, they will be able to share the tank successfully (for example betta, angelfish). It’s worth mentioning that freshwater shrimps (like cherry shrimp) may be the fish prey.
Gender differences: male vs female
Determining the sex of dojo loaches (Misgurnus anguillicaudatus) can be challenging, as these fish do not exhibit pronounced physical differences. However, there are subtle cues that can help you identify mature individuals.
Physical Characteristics
- Body Shape: Mature females typically have a rounder and plumper body shape, particularly noticeable during the breeding season when they may appear fuller due to developing eggs.
- Fin Rays: The anal fin of mature males may exhibit slightly thicker or more prominent fin rays, although this difference can be subtle and difficult to observe.
Behavioral Differences
During the breeding season, male dojo loaches often display more active and competitive behavior, including chasing or nipping at other males in an effort to attract females. While this behavior can serve as a clue, it may not be observable outside of breeding periods.
Practical Tips for Identification
Given the challenges of sexing dojo loaches based solely on physical traits, consider observing their behavior during breeding seasons. Additionally, purchasing a group of dojo loaches can increase your chances of having both males and females. Breeding behavior, along with the presence of eggs or fry, will confirm the sex of your fish.
Breeding
Information about breeding dojo loaches (Misgurnus anguillicaudatus) in captivity is often fragmented. In commercial farm hatcheries, it is likely that hormone injections are used to stimulate breeding, as this species is highly sought after by aquarists, the food industry, and scientific researchers.
Breeding in the Wild
In their natural habitat, breeding occurs when a male dojo loach engages in a mating display, embracing the female to fertilize the eggs she lays. The female typically deposits around 100 to 150 eggs among algae, where the eggs—approximately 1.7 to 1.9 mm in diameter—sink to the substrate. These eggs are light brown and not very sticky, allowing them to settle easily.
Development Stages of Larvae
At a water temperature of 14 to 16 °C, the egg stage lasts about four days before the larvae hatch, equipped with external gills for respiration. Additionally, a dense network of blood vessels in the large pectoral fins and later in the intestinal tract aids in respiration.
By the twelfth day, the larvae measure around 8 mm and begin to seek food using specialized sensory organs located around their mouths and on their barbels, which develop early in life. By the age of 26 days, their external gills are fully reabsorbed, marking the transition to the juvenile stage, which occurs when they reach about 30 mm in length.