If you want an efficient cleaner fish that won’t grow too large and is a peaceful community member, the Kuhli loach (Pangio kuhlii) might be what you’re looking for.
Kuhli loaches are bottom-dwellers, coming out at night to scour the substrate for scraps of food. These attractive fish can be highly sensitive to water conditions and fish medication, so we do recommend that you have some fishkeeping experience if you want to keep them.
To find out more about these colorful, eel-like fishes and how to care for them, read on!
Kuhli Loach – Overview
Common Name (species)
Kuhli loach, Coolie Loach, Giant Coolie Loach, Leopard Loach, Cinnamon Loach
Southeast Asia; Sumatra, Singapore, Western Malaysia, Java, Borneo, and Thailand.
Omnivore, prefers live foods
Bottom-dwelling, active scavengers
Up to 10 years
Peaceful community fish
Bottom-dweller during daylight, all areas at night
Minimum Tank Size
Tropical 73° to 86° Fahrenheit
0 – 5 dGH
5.5 to 6.5
Likes well-oxygenated, clean water and a good flow rate
Egg layer, challenging to breed in home aquariums
Peaceful with small, non-aggressive community fish
OK, for Planted Tanks?
Safe with plants
The Kuhli loach (Pangio kuhlii) was previously known as Acanthophthalmus kuhlii and was first described by Achille Valenciennes in 1846.
Today, Kuhli loaches are found in Southeast Asia, Singapore, Sumatra, Western Malaysia, Borneo, Thailand, and Java. The species is not currently listed or evaluated on the IUCN Red List of Endangered Species.
In their wild environment, these loaches inhabit slow-moving rivers and mountain streams. The substrate here is predominantly soft and sandy and covered with leaf litter that falls from the overhanging, shady forest canopy.
Although they’re not natural schooling fish, Kuhli loaches are often found living in small groups of their own kind.
The fish’s body is pinkish-yellow, crisscrossed by 12 to 17 dark vertical bands, and there are three dark bars across the head. The Kuhli loach’s head is scaleless. The eyes are covered by a transparent skin and protected by a short spine in front of them. Kuhli loaches have three pairs of whiskery barbels. The loach’s dorsal fin is set far back, and the anal fin is located at the end of the dorsal.
Kuhli loaches can also be found in albino form, known as the Albino Kuhli loach. The albino form is artificially created through captive breeding and is not thought to occur naturally in the wild population.
Kuhli loaches are small, worm-like creatures that generally grow to reach between 3 to 4.5 inches in length, although they are often a little smaller than that in the aquarium.
Kuhli loaches generally live for up to ten years in captivity, provided that they receive good care and a high-quality diet.
Kuhli loaches are peaceful fishes that get on well with most other community species.
These fish are mainly nocturnal, emerging when the aquarium lights go out to scavenge for food on the tank’s bottom. Kuhli loaches are incredibly active fish, swimming all over the aquarium during the night and providing quite a show that you can watch if you have a moonlight feature on your LED lighting unit.
During the daytime, the loaches hide in caves and crevices, leading to calamity if you leave your filter inlets unprotected and the worm-like loaches wriggle inside to seek shelter.
Kuhli loaches also enjoy burrowing in the substrate.
Compatibility and Tankmates
Safety in numbers
Although they’re not naturally shoaling fish, the loaches are more relaxed and settled if kept with a few companions of their own kind. Another reason for offering your Kuhli loaches is that they can be very shy creatures when left alone, so you have more chances of seeing them if they have a few friends to give them confidence.
Kuhli loaches are peaceful, amenable fish that spend the majority of their time swimming around the bottom of the tank. So, although other small peaceful catfish species such as corydoras can make suitable companions in a large, spacious tank, loaches tend to do best with other sociable species that hang out in the upper area of the water column, such as tetras, danios, and rasboras.
You can also include invertebrates such as shrimp, and larger peaceful fish, including dwarf gouramis in the community.
Fish to Avoid
To ensure harmony in the tank, don’t add large species of territorial fishes such as Oscars and cichlids. Bullies and fin nippers, including Tiger barbs and Angelfish, are also best avoided.
Although small snails can be useful as algae eaters, they don’t mix well with Kuhli loaches that may view the mollusks as a food source.
One crucial aspect of fishkeeping is feeding your fish a high-quality, correct diet in the right amount.
What to Feed Your Kuhli Loaches
Kuhli loaches are omnivores. In nature, the fish eat small crustaceans, plant matter, and insect larvae that they find on the substrate.
In captivity, these fish are scavengers, spending much of their time foraging around on the bottom of the aquarium and eating whatever morsels of food drift down from above. A good diet for Kuhli loaches includes high-quality fish flakes or pellets, live and frozen meaty foods, such as bloodworms, daphnia, grindal worms, brine shrimp, and micro-worms.
How Much and How Often to Feed
When feeding your loaches, remember that they are most active at night. So, the best time to feed the fish is just before lights out and first thing in the morning. If you have moonlighting in your tank, you’ll be able to enjoy watching the frenetic activity that will ensue when you drop the loaches’ food into the water!
I suggest that you feed your loaches twice a day, offering just enough food to last them for a couple of minutes or so.
All fish species do best when kept in an environment that replicates their natural, wild habitat. So, bear that in mind when setting up a tank for your loaches.
We recommend a tank of at least 20 gallons for Kuhli loaches, allowing three to five gallons of water per loach.
As loaches are lively bottom-dwellers, it’s best to use a rectangular tank with plenty of floor space rather than a tall, deep setup.
Kuhli loaches can jump, so choose a tank with a cover slide or tightly fitting lid.
A soft, sandy, or fine gravel substrate is the best choice for the bottom-dwelling Kuhli loaches.
In nature, the loaches’ natural habitat is heavily vegetated, so the aquarium should provide plenty of lush planting. The water bodies that the loaches inhabit are typically overhung by the forest canopy, and the substrate is covered in leaf litter. You can use dried almond leaves or peat to produce a similar effect in the aquarium.
Loaches like to hide away during the daytime, so include some driftwood, caves, tangled roots, and large rocks.
Kuhli loaches like well-oxygenated, clean water, so we recommend that you use an undergravel filter with a pump that provides a turnover rate of at least ten times per hour. It’s also a good idea to add a powerhead or canister filter to provide the ideal current for these loaches.
Make sure that you cover the inline and outlet pipe of your filter system so that the loaches can’t swim inside and become trapped.
Kuhli loaches are tropical fish that need a water temperature of 73° to 86° Fahrenheit.
Water Hardness and pH Range
The aquarium water should be on the soft side with a hardness of between 0 and 5 dGH, and the pH should be slightly acidic in the range of 5.5 to 6.5.
To replicate their natural habitat, the lighting in the Kuhli loaches’ tank should be subdued. You can help to diffuse the light by using a raft of floating plants.
Kuhli loaches need pristine, extremely well-oxygenated water if they are to thrive. For that reason, we recommend that you perform 30% water changes every week.
You can help to keep the water clean and reduce the bioload on your biological filtration system by deep-cleaning the substrate once a week with an aquarium vacuum. Pay particular attention to hotspots, including underneath decorations, around the bottom of plants, and in the corners of the tank.
Clean and replace the filter media and sponges regularly in line with the individual manufacturers’ recommendations.
Setting Up the Aquarium
Because of the Kuhli loach’s sensitivity to water conditions, I don’t recommend introducing these fish to a brand new or immature aquarium. It’s generally better to wait until your tank has had a chance to settle down and fully stabilize before adding loaches.
To set up your tank from scratch, begin by assembling all the items that you need:
- Sandy or fine gravel substrate
- Lighting unit
- Filtration system
- Aquarium thermometer
- Decorations, including driftwood, twisted roots, rocks, and caves
- Dried almond leaves
How to set up your tank:
- Rinse the substrate under running water to get rid of dust and debris. Even prepared, ready-rinsed substrate tends to have an amount of loose dirt, so it’s always advisable to wash it first.
- Put the cleaned substrate into your tank to a depth of about two to three inches.
- Install your heater and filtration unit in the tank, but don’t turn them on yet.
- Next, fill the tank with water. To avoid displacing the substrate when you pour the water into the tank, place an upturned bowl on the substrate and slowly pour the water over it.
- To begin the nitrogen cycle in the biological filter media, the water needs to contain ammonia. So, treat the tap water with a water conditioner to remove harmful chlorine or chloramine, and then add some drops of pure ammonia, a pinch of fish food, or some substrate from an established tank.
- Wash the tank decorations to remove dust, and add them to your tank.
- Trim off dead stems and snip away any brown or dead leaves from your live plants. Allow plenty of space between the plants so that they can spread and grow properly, placing low-growing varieties at the front of the tank and taller species in the background.
- Activate the filtration system and heater, and then allow the tank to cycle for at least ten days before you introduce your fish. If you’ve included live plants in your setup, switch on your tank lights for eight to ten hours per day.
- After ten days have elapsed, test the water. The levels of ammonia and nitrites should be at zero, and nitrates should be a maximum of 20ppm. If the levels are higher than that, the tank is not fully cycled, so allow another few days to elapse before retesting the water.
Health and Disease
Although Kuhli loaches are pretty hardy fish, they’re not recommended as fish for beginners. These fish have very small body scales and no scales on their heads at all. That makes the fish more susceptible to diseases, as well as rendering them highly sensitive to most medications.
Signs of Good Health
Kuhli loaches tend to hide during the daytime, coming out at night to scavenge and socialize with their group.
These loaches are generally extremely lively and active at night, scurrying around all areas of the tank in search of food.
There are a few red flags that can alert you to health problems in your loaches, including:
- Not eating.
- Appearing mainly during the daytime.
- Inactivity at night.
- Swellings, ulcers, and reddened areas on the skin.
- Rubbing against objects in the tank or on the substrate.
Common Health Issues and Treatment
Ich (White Spot Disease)
Skin and gill flukes
Symptoms or Causes
Ich is a common disease of tropical and coldwater fish that’s also called White Spot disease.
Ich is caused by a protozoan parasite, manifesting as a rash of white spots across the fish’s body, gills, and fins. Fish with Ich usually flick against objects in the tank in the early stages of the disease.
Flukes are parasites that attach themselves to the fish’s body and gills. Infected fish rub against the substrate and solid surfaces within the tank, as well as secreting excessive mucus.
White cotton-like growths.
Reddened patches on the skin, ulcers.
Skinny disease commonly affects loaches. If the fish are eating well but losing weight, it’s likely that Skinny disease is the culprit. Internal parasites cause the disease.
Raise the water temperature to 82o F for three days, and treat the water with a loach-safe over-the-counter medication.
Treat the whole tank with loach-safe anti-parasitic medication.
Quarantine affected fish; treat the water with loach-safe antifungal medication.
Quarantine affected fish; dose the aquarium with loach-safe antibacterial treatment.
Treat the tank with loach-safe antibacterial medication.
Although it is very difficult to raise Kuhli loaches in the home aquarium, it can sometimes be done if a spawning tank is used.
Boys or Girls?
Loaches are communal spawners, so you have more chance of success if you keep a mixed group of specimens. So, how do you tell the boys from the girls?
On sexually mature male Kuhli loaches, the first ray of the pectoral fin is thickened and branched. Fully-grown female specimens are generally heavier-bodied and larger than their male counterparts. Female fish that are carrying eggs are plumper than males.
In the spawning tank, the light should be dim, and the water shallow.
Include lots of floating plants to diffuse the lighting and provide a place where the females can lay their eggs. Dense vegetation also helps to encourage spawning.
Keep the pH levels at around 6.5.
Offer the fish plenty of live foods to bring them into prime breeding condition.
When the females are almost ready to lay their eggs, you might be able to see the eggs through the fish’s skin.
When the bright green eggs are laid, they will stick to the underside of the floating plants, hatching after about 24 hours. The adult fish will eat the eggs and fry, so be sure to remove the adults once the eggs have been laid.
Feed the fry with baby brine shrimp, infusoria, and commercially prepared fry food.
You can find Kuhli loaches for sale in most good fish stores and online for just a few dollars per specimen.
- A fishnet
- Algae magnet
- Aquarium thermometer
- Aquarium vacuum
- Books on keeping tropical fish
- Filtration system
- Fish tank (minimum size 20 gallons)
- High-quality tropical fish flakes or pellets
- Lighting unit
- Plants, including floating species
- Rocks, driftwood, twisted roots, caves
- Sandy or fine gravel substrate
- Selection of frozen foods
- Water conditioner
I hope you enjoyed our guide to caring for the fascinating Kuhli loach.
Do you keep Kuhli loaches? Have you bred these fish in your home tank? Tell us in the comments box below.
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