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The Kuhli Loach is a freshwater fish found in the tropical regions of southeast Asia, which include China and the Philippines. They’re a very unique looking fish that features long eyelashes, long whisker-like barbels (known as mystacial vibrissae), and a slim body that resembles that of an eel.
If you are new to the aquarium trade, I’d recommend reading the complete fish care guide for a better understanding of basic aquarium keeping information.
- Kuhli Loaches are bottom dwellers that burrow in the substrate
- They grow to 4 inches in length and can live up to 15 years
- They are peaceful and do great in community tanks
|Scientific Name||Pangio Kuhlii|
|Common Names||Coolie Loach, Slimy Loach, Leopard Loach, Giant Coolie Loach, etc.|
|Origin||Southest Asia (Indonesia and Malaysia)|
|Activity||Nocturnal active fish species|
|Lifespan||10 to 15 years|
|Tank Level||Bottom Dweller|
|Minimum Tank Size||20 gallons|
|Temperature Range||73 to 86° F|
|Water Hardness||3 to 10 KH|
|pH Range||5.5 to 6.5|
|Difficulty to Breed||Difficult|
|OK, for Planted Tanks?||Yes|
What Is It?
Kuhli loach, also known as Coolie Loach, Pangio kuhlii, or Acanthophthalmus kuhli belongs to Indonesia and can be commonly found in Singapore, Malaysia, Borneo, and Java. They occupy the bottom of the tank and are scavengers with downward-facing mouths and protruding four pairs of barbels. Kuhli loach is a nocturnal and social animal that enjoys the company of members of their own species.
Kuhli loach is also known as Prickle eye because of the presence of a prickle near their eyes. The prickle near the eyes of Kuhli loach provides protection from predatory fish.
Origin and Habitat
The Kuhli loach or Pangio kuhlii, Coolie Loach is native to Indonesia, Malaysia, and Thailand. Their natural habitat is near the south of the equator where the water is warm and the temperature is around 75 and 86 degrees Fahrenheit.
Kuhli loach is an eel-shaped fish with an elongated, scaleless fish body.
Their shape and color combination is more like a snake than a fish. At first glance, it is impossible for novice fish keepers to distinguish the Kuhli loach from eels. Also, they have alternating dark and light color bands that circle their bodies. Like snails or eels, Kuhli loaches slither at the bottom of the tank. The bodies of Kuhli loach are thin with relatively smaller fins and eyes covered in transparent skin. While it has a dorsal fin, it is located much closer to the tail then with other fish.
There are other subtypes of this species as well. These would be the Silver Kuhli Loach. It’s native to Southeast Asia and has a round pointed tail.
Like all scavenger fish, the mouth of Kuhli loach is downward facing with protruding barbles that contain taste buds.
The color of Kuhli loaches is one of the most distinctive characteristics. They are multi-colored with a light pink to brassy yellow base. And over the base color, you can find at least 10 to 15 dark brown stripes.
Wild kuhli loaches grow around 5 inches in length. However, in captivity, Kuhli loaches grow around 3 to 4 inches long.
Under the right conditions, Kuhli Loach lifespan can be between 10 to 15 years. The adult Kuhli Loaches are medium-sized fish. Your fish will grow slowly but steadily throughout their life, and adults can reach a length of 3 to 4 inches (7.6 to 10.1 cm).
Kuhli Loaches are a hardy beginner fish that get along with a variety of other fish. They are also tolerant of cold water and are active when most fish are not. Let’s look into what’s required for their care.
It’s vital that you research your Kuhli Loach thoroughly before you decide to keep it. I can’t stress enough how many people get this fish only to realize later that Kuhli Loach isn’t the best choice for their aquarium. Often, the time and money spent on the Kuhli Loach are wasted. You might as well just replace them if you’re not taking good care of them.
The ability of these fish to adapt to pollution is amazing. But that doesn’t mean they can survive any amount of it. You still have to be very careful about your home aquarium conditions. When you’re introducing a new Kuhli Loach, keep a close eye on water quality and temperature until you’re certain they’re acclimated. Overfeeding your Kuhli Loach can also cause problems. Unfortunately, they do like to eat a lot.
Kuhli Loaches are a very social fish and should ideally be kept in groups of at least three, but larger groups are definitely better. They are not very aggressive towards other fish but may eat smaller fish. This can be prevented by keeping them with larger, peaceful tank mates. They also frequently nip at plants, so keeping them with fast-growing plants (such as swords) may be beneficial.
Kuhli Loach fish are very striking in appearance, with their black vertical stripes against yellow and orange body colors. As I mentioned above, they’re very active fish, and they love to play together.
Tank Setup and Size (Miniumum Tank Size)
A 10-gallon tank will work well. If you want to keep a pair. However, if you want to give the fish space to grow, you should set up a 30-gallon aquarium.
Then again, you don’t want to crowd them either. As a general rule of thumb, you should never have less than 10 gallons of water per fish. This will give them plenty of room to swim, hide, and thrive.
Water Parameters (Tank Conditions)
Kuhli loaches love it when their natural habitat is imitated. And thus, they prefer slow-moving water with water temperatures around 73 to 86 degrees Fahrenheit.
As for the water, they like it slightly acidic with a pH range of around 5.5 to 6.5. Also, the water hardness should be no more than 5 dGH.
Filtration and Aeration
Filtration rate: 2 to 3 times the aquarium water volume per hour is a good range for Kuhli Loach aquariums.
Being scavengers, Kuhli Loaches are aware of their surroundings. Any change in condition or food is quickly recognized by them. They can leave your aquarium quickly if you are planning to take a vacation for some days. So they help in maintaining a clean fish tank.
If the tank is not cleaned properly, high nitrate & phosphate levels develop that can harm your loaches. Kuhli Loaches need a high level of oxygen in the water to survive. Since they are bottom dwellers, they need to be given some sand as they clean their selves daily on the substrate. They love to dig in the sand too. Allow them to engage in their burrowing habits but purchasing a finer substrate.
Canister filters need a good flow of water to work properly. They are not the best option if you are setting up a small aquarium. However, they are the best mechanical aquarium filters that clean your aquarium water. They can help tank owners keep their fish healthy.
The lighting should be moderate to low in an aquarium setting. I advise investing in a dimmable, adjustable LED light.
Aquatic Plants and Decorations (Aquarium Environment)
Kuhli Loaches are nocturnal and emerge from the safety of rockwork, caves, and underneath dense foliage to feed at night. During the day they like to hide out in the dark, so provide plenty of places for them to hide, including driftwood or rock hiding places, as well as leaf litter. Kuhli loaches need a lot of space to explore and should be kept in a minimum 10-gallon aquarium if possible.
If you plan on having plants and clay or black substrate, it is a good idea to break up large clumps of the substrate or use fine gravel as a substrate. Avoid the use of crushed gravel, as it can harm delicate loach eyes. Sandy substrate is highly recommended.
It is important to not handle the fish roughly; they are delicate fish that are susceptible to barotrauma and swim bladder disease.
Community Tank Mates
They won’t bother fish that like to hang out at the top or mid-levels of the tank. Pairing a Kuhli Loach with some Smaller cichlids. You can also add some South Asian loaches, catfish, and eels. If you want to get really creative, you can find some other species of fish that are native to the same area as your loaches.
So having a mid-to-bottom dwelling fish with them is a good idea. One of the best tank mates for them would be freshwater snails, red cherry shrimp, and small catfish (Corydoras). While you’ll almost never see them interacting with other fish, this species is very social. They swim in groups and sometimes even bury themselves in substrate right next to each other.
Avoid putting them with larger, aggressive fish such as large cichlids. Aggressive fish that are smaller or territorial where they swim at (the bottom of the tank) should also be avoided.
Breeding Kuhli loaches is a daunting task because sociability is the major reason for their daytime disappearance. While kuhlis tolerate each other very well in the confines of a small tank, they tend to squabble when kept in a large group (video source).
As a general rule, it is best to keep no more than three kuhlis per tank. If you have a tank that is large enough to leave them alone (such as 100 gallons or more) and you choose your initial stock wisely, you can keep larger groups than that.
Unfortunately, as Kuhli Loaches mature and start looking for mates, they become shy once again. Both sexes become sexually mature in the first year of their long five-year lifespans (which is longer than much other fish). The dominant male and female will pair up and start to call each other. The eggs are laid on a flat surface, usually a driftwood root or rock.
Still, if you do want to see your fish exploring your tank, there are a few things you can do. 1. 1. 1. First, make sure the tank is large enough.
- If it has too many hiding places, it can be claustrophobic for the fish.
- Try adding a few more fish. The more loaches you have, the more likely it is that there will be someone out and about.
- Finally, try changing the tank’s decor a bit.
Filtration for a kuhli loach separate breeding tank needs to be strong enough to keep ammonia levels low. With a group of kuhlis, the bio-load on the aquarium water is significant and filtration must be able to handle it. The loaches are extremely sensitive to ammonia and nitrite, they will hide, stop eating, and if the levels get too high, will die.
Setting up a separate breeding tank
To breed kuhli loaches, you need to set up an aquarium tailored to their requirements
- Fill the tank with water and then add a thin layer of sand (1/2 inch should be plenty).
- Add lots of hiding place for kuhlis
- A fluorescent light about three inches above the tank will serve to provide enough light for plants. I’ve also had good luck with floating plants like water lettuce, which will provide a food source for the fry. The fish will lay their eggs in the space between the saucers and the side of the tank and both parents will guard them.
- You can also add salt to your water to encourage the adults to spawn, you’ll want a small pump-driven powerhead to circulate that salt water. Keep the salinity at 1.005 to 1.010.
- Set the aquarium lights on a timer, it’s best if you turn them on before getting up in the morning and turn them off in the evening.
- Get an aquarium thermometer that reads in tenths of degrees and can be easily attached to the glass.
- The temperatures should be between 20 degrees C and 24 degrees C (about 70 degrees F to 75 degrees F).
I recommend using a piece of slate tile as the platform because it is easy to clean, and the little “potholes” (little crevices between individual pieces of slate) will provide a safe haven for the fry. A single male with six to 12 females, depending on the size of your tank, will be a good ratio for starting out. If you have less than six female kuhlis, there will not be enough eggs for the male to fertilize.
Food and Diet
Since Kuhli loaches live at the bottom of the tank and are scavengers, they pretty much eat anything accessible to them. But it’s recommended to provide them with regular meals. Kuhli loaches love:
- Plant material
- Insects and larvae
- Brine shrimp
- Grindal worms
- Fish Flakes and pellets
- Frozen bloodworms
The fry of Kuhli loach should be given commercial fry foods or infusoria for the first week of their life.
How often should you feed?
Loaches should be fed at least twice per day but no more than four times per day. That too, only if they can finish their food in 3 to 4 minutes.
Do they eat snails?
Many aquarists get Kuhli loaches because they want to eradicate snails from their home aquariums. Upon asking a few friends, I received mixed answers. Some said they noticed a significant reduction in the eggs of the snails while others said Kuhli loaches did not affect the population of snails at all. Therefore, it is not proven that Kuhli loach will steer your aquarium clean of snails.
However, since it’s a scavenger and despite being a peaceful fish, an opportunistic eater, Kuhli loaches eat snails with damaged shells or dying snails. Again, it’s not proven.
Common Health Problems
Kuhli loaches are one of the hardiest freshwater fish I know. However, like other fish species, the well-being and life expectancy of kuhli loach depend on water conditions and aquarium requirements.
Kuhli loach diseases are rare, but not uncommon in the aquarium fish industry.
If you notice red streaks on your Kuhli loaches, chances are it’s suffering from bloating. Bloating can be treated by exposing the Kuhli loach fish in 10 to 20 percent saltwater at room temperature.
- Bloated stomach
- Expanded scales that allow more air to enter the body
- Eyes sunken into the eye sockets
- Swollen fins
Skinny or Wasting
Surprisingly, Kuhli loaches may appear healthy and happy while deep inside, they are getting skinner even after multiple feedings. This condition is called skinny or wasting.
- Protruding stomach
- Visible spine and ribs
Like any other freshwater fish, Kuhli loaches can get Ich. However, unlike other fish, the symptoms of ick in Kuhli loaches are mild. The early diagnosis of Ich help in the fast treatment of the disease. However, if it’s more severe, proper medications need to be administered. Also, you may need to quarantine the fish for at least 10 to 14 days.
- Erratic movements
- Scratching the bodies against sharp objects in the tank
Differences Between Male and Female Kuhli Loaches
The difference between male and female Kuhli loaches lies in the bodies. Male Kuhli loach has a leaner body as compared to females. Also, the pectoral fins in males are bigger, resembling the shape of a paddle than females.
How many should be kept together?
Kuhli loach is a social freshwater fish species that grow around 3 to 4 inches long. It’s recommended to keep a group of at least 6 Kuhli loaches in a 20-gallon tank.
Can you keep a single one?
No, Kuhli loach is not a schooling fish. But it enjoys company and prefers to stay in groups. A single kuhli loach will feel insecure and never come out to explore the tank. Hence, it will remain stressful and show abnormal behaviors.
What are they good for?
Since Kuhli loach is a scavenger, scaleless fish produces less waste as compared to others. Many fish hobbyists prefer to keep them as cleaner fish.
However, it makes excellent tank mates for most fish and has a brilliant appearance that makes them an ideal fit for most tanks.
Do they need to be in groups?
Yes, Kuhli loach is not schooling species. But they are always happy to be in a group of at least six or more.
Do the black ones need to be in groups?
Yes, like Pangio kuhlii, the black kuhli loach also likes to be in a group of at least six or more in a 20-gallon tank.
What do the black ones eat?
Like Pangio kuhlii, black kuhli loach is an omnivore that eats plant matter as well as meat content. You can feed black kuhli loach:
Insects and larvae
Flakes and pellets
Can the black ones live alone?
No, the black kuhli loach is also a social creature that enjoys the company of more kuhli loaches and other fish species. Therefore, it is not recommended to keep them alone. The tank mates for Black Kuhli loaches are the same as the Pangio kuhlii.
Do the black ones eat shrimp?
Yes, Black kuhli loach will eat shrimps and any other small fish since they are opportunistic feeders.
Kuhli Loach is a unique eel-like peaceful fish that can be a beautiful addition to your aquarium. They are non-aggressive fish and natural tank cleaners that eat anything at the bottom of the tank except your aquatic plants.
They are hardy freshwater fish species and easy to care for. Just take care of their environment and food and be prepared to nurture them for at least 10 years.
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