The Kuhli Loach Pangio kuhlii is an active, fascinating little fish. Its behaviors are typical of all members of the Pangio genus. It keeps in almost constant motion, actively scurrying around, over, and through the plants and ornamentation. It is scavenging for leftover foods that have settled on the bottom of the aquarium. This is a great little helper in keeping the aquarium clean and in good shape..
This little fish was originally named and is best known as the Kuhli Loach or Prickly Eye, but there are quite a few other common names often associated with this fish. For example, in the United States this loach is sometimes also called the Coolie Loach, Giant Coolie Loach, Leopard Loach, and Cinnamon Loach. Coolie Loaches are exported by the millions for the aquarium hobby.
Though peaceful, the Kuhli Loach is nocturnal and is most active at night. They can also be quite shy and will seldom be seen if kept alone. This doesn't mean they are a schooling fish, as they are not, but they are more comfortable and more likely to come out of hiding if they have some companions. A group of a half dozen or so will make them more prone to behave as they would in nature. They are quite hardy and can live for several years.
The term 'kuhli loach' is often used collectively to refer to a group fish in the Pangio genus (previously the Acanthophthalmus genus) that are much like the actual Kuhli Loach. These loaches all have the elongated wormlike body shape, are fairly similar in size and appearance, and are also wiggly little scavengers who make great aquarium cleaners. Each of these fish however, can be distinguished from the Kuhli Loach by their individual color patterns and adult size.
The Kuhli Loach Pangio kuhlii (previously Acanthophthalmus kuhlii) was described by Valenciennes in 1846. They are found in southeast Asia; Sumatra, Singapore, western Malaysia, Java, Borneo, and Thailand. This species is not listed on the IUCN Red List. Other common names they are known by include Prickly Eye, Coolie Loach, Giant Coolie Loach, Cinnamon Loach, and Leopard Loach.
They live in sandy areas of slow- moving rivers and mountain streams covered in leaf litter. Their habitats are normally shaded from the sun by the forests canopy. In nature these loaches are found in small groups, however they are not schooling fish.
Scientific Name: Pangio kuhlii
Social Grouping: Groups - Not actually schooling fish, but are usually found in clusters of their own kind.
IUCN Red List: NE - Not Evaluated or not listed
The Kuhli Loach is a smaller, worm-like loach that can reach from 3 - 4 1/2 inches (7.8 - 12 cm) in length, though generally a bit smaller in the aquarium. Their life span is generally about 10 years, though they been reported to live even longer.
This loach's body has a pinkish yellow background color crossed by 12 to 17 vertical dark bars and has three bars on its head. There are no scales on the head, the eyes are covered by a transparent skin with a short spine in front of them, and they have 3 pairs of whisker-like barbels. The dorsal fin is set very far back, and the anal fin is set at the end of the base of the dorsal fin.
Their is also an albino color form of this Loach, known as the Albino Kuhli Loach. This a bred color form, and it is not certain whether the Albino Kuhli Loach occurs naturally in the wild. But these would be highly visible animals, so beacons for predation.
Size of fish - inches: 4.7 inches (11.99 cm) - These fish can get up to about 4 1/2 inches (12 cm), though they are usually smaller in the aquarium.
Lifespan: 10 years - This fish generally has a lifespan of about 10 years, but has been reported to live longer.
Fish Keeping Difficulty
This loach can be hardy under the right conditions. They are not recommended for beginners because of their need for pristine water and having small body scales and no scales on the head. Reduced scales makes them more prone to disease and very sensitive to medications used to treat disease. Experience in treating scaleless fish is very important to be able to give your loach a healthy and long life. Do not try to introduce these fish into biologically immature tanks.
Aquarium Hardiness: Moderately hardy
Aquarist Experience Level: Intermediate
Foods and Feeding
Since they are omnivorous, the Kuhli Loach will generally eat all kinds of small live and frozen foods and meat based foods are relished the most. They also like sinking pelleted and tablet foods, flakes, and a bit of vegetable foods such as algae wafers. To keep a good balance give them a high quality prepared food everyday. Feed tubifex worms, brine shrimp (either live or frozen), mosquito larvae, and daphnia as a treat.
Diet Type: Omnivore
Flake Food: Yes
Tablet Pellet: Occasionally
Live foods (fishes, shrimps, worms): Some of Diet
Vegetable Food: Some of Diet
Meaty Food: Most of Diet
Feeding Frequency: Several feedings per day
The most important thing for these loaches is that they always have clean and well-oxygenated water. Frequent water changes of about 30% a week are needed for the Kuhli Loach. With your weekly water change make sure to vacuum the gravel to remove all excess food and waste, but It's best not to remove any bio film on rocks and decor. A magnet algae cleaner normally does a great job in keeping the viewing pane clear.
Water Changes: Weekly - 30%
The Kuhli Loach will swim mostly on the bottom of the aquarium, but at night these loaches will swim all over the tank. Never introduce this loach into a biological immature setup as these fish require pristine water. This fish will do well in a medium sized aquarium (ideally 20 gallons or so) with soft, slightly acidic water and subdued lighting. They need good water movement that provides plenty of oxygenation. The tank water should turnover at least 10-15 times per hour. An undergravel filter is a great choice for these fish as it creates high oxygen through out the tank as well as reducing the waste. Adding a canister filter or power head to the setup will make the proper current for this loach.
The decor with for fish is really up to personal taste, but the substrate needs to be a fine gravel or sand that does not have sharp edges. They will also enjoy a bit of peat moss spread over the substrate to simulate the natural mulm found in their native environment. Some smooth water-worn large rocks and stones should be scattered throughout along with a couple pieces of driftwood and some twisted roots will make a great place to retreat. These loaches are very inquisitive and like to explore so make sure to have a lot of caves and crevices. These fish can and will jump out of the tank if given the chance so make sure to have a tight fitting cover.
Minimum Tank Size: 20 gal (76 L)
Suitable for Nano Tank: Yes
Substrate Type: Sand/Gravel Mix
Lighting Needs: Low - subdued lighting
Temperature: 73.0 to 86.0° F (22.8 to 30.0° C) - Though best kept in the 70's, They can tolerate the low 80°s for a short period.
Range ph: 5.5-6.5
Hardness Range: 0 - 5 dGH
Water Movement: Moderate
Water Region: Bottom - These fish are mostly bottom dwellers but will swim in all areas of the tank at night.
This loach is a peaceful community fish and a great scavenger of uneaten foods that settle to the bottom of the aquarium. They hide during the day, but are quite lively and active in the evening. Though they do not school, they will be more likely to come out of hiding if they are kept with some companions. A singly kept Kuhli Loach will seldom be seen. It is recommended that they be kept in small groups of at least 6 or more of its own kind.
Same species - conspecifics: Yes - Best kept in groups of 6 or more, if kept singly a Kuhli will seldom be seen.
Peaceful fish (): Safe
Semi-Aggressive (): Monitor
Aggressive (): Monitor
Large Semi-Aggressive (): Threat
Large Aggressive, Predatory (): Monitor
Slow Swimmers & Eaters (): Safe
Shrimps, Crabs, Snails: Safe - not aggressive
Sex: Sexual differences
On mature males the first ray in the pectoral fin is branched and thickened. Adult females are typically heavier-bodied and a little larger then males. Female with eggs will also be plumper.
Breeding / Reproduction
Although they have been bred successfully in the aquarium, not much is known about the breeding habits of the Kuhli Loach. They scatter bright green adhesive eggs underneath floating plants where the eggs then attach to the stems and roots. The eggs have been described by Herbert Axelrod as a type of bubble nest, with each egg enclosed in a bubble. They are not yet bred commercially.
Ease of Breeding: Difficult
Loaches are more susceptible to disease than other aquarium fishes. This may have to do with the faint body scales and no head scales. So take caution when introducing these fish to an established tank. They are also very sensitive to different medications used to treat many diseases; a separate hospital tank is needed. Cold water and condition changes can also cause stress to this fish which makes them even more prone to disease.
Most common disease that affects this loach is Ich. Ich is short for Ichthyophthirius, also known as "white spot disease". It is a parasite that can attack nearly all aquarium fishes, but you'll find that loaches are often the first to be attacked. Take great care in treating ick as loaches are very sensitive to the medications used to treat it. Often the dose is half of what is normally used.
The second most common thing that affects loaches is a thing called skinny disease. This can be diagnosed fairly easily. If your loaches are eating a nitrous and healthy amounts and still seems to loose weight it is a good chance it has skinny disease. This is caused by internal parasites and can be treated with medication if used carefully.
An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping these sensitive types of fish, it is common to catch deteriorating water conditions and disease before other fish are affected. The best way to proactively prevent disease is to give your Kuhli Loach the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease.
Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Kuhli Loach is readily available at pet stores and online, and is moderately priced.
Maria Anderson - 2015-04-26 Hi, I'd very much like some feeding advice! I have three Corydoras aeneus and three Pangio kuhlii. The Cordy's absolutely throw themselves over the pellets and tablets that I give them twice a day, and there's really nothing left for the Kuhlii guys once they are done! The Kuhlii's come out from their hidingplaces every now and then, but they always comes out too late when it's feeding time! The Cory's has cleaned the plate, so to speak, and left nothing! And even if I see the Kuhlii's and try to make a tablet sink closeby to them, the Cory's are like missiles and eats that tablet too! How do I make sure that the Kuhlii's gets properly fed too?!!!
Clarice Brough - 2015-04-28 The Corydoras are simply more active, and they love to eat! Neither of these fish are aggressive, it's really about their natural activity levels. The Kuhlii are more reserved, as you've seen, so it may take a separate tank for each to make sure your Kuhlii don't end up starving.
Liam - 2015-02-24 Help, I have 2 Kuhli Loaches and I am keeping them in a medium tank with 4 guppies and a dwarf gourami. The two loaches seem to be floating on the surface of the water all the time and never seem to be able to stay at the bottom. The also have been climbing onto the suction cup of the heater and staying partially out of the water, they were doing this before they started floating. If anyone knows anything please help.
Clarice Brough - 2015-02-24 This does happen with Kuhli Loaches, and it's often related to tank conditions and water changes. They need soft, slightly acidic water with good movement so that there is also plenty of oxygen. They always have to have very clean water, and it helps if each partial water change is relatively small.
It's said that hardness changes due to new water can be one of the reasons they float. You need to know the pH and hardness of your tap water and of the water in your tank. Then the replacement water needs to be adjusted to have the same hardness as the tank water, to help avoid problems like osmotic shock. Hope this helps.
Connor - 2014-10-16 I have two community tanks and I have 4 kuhli loaches, two in one and two in the other. And in my main tank they come out all of the time but in my littler tank I hardly ever see them. They are gorgeous fish to keep and also they like to come out at night. These are lovely fish to have so I recommend you get these. If you know why my other khuli loaches don't come out please let me know?
I had two Pangio Kuhil loach's that were doing fabulous, I bought another two yesterday and now three are swimming like they have something after them, they swim quickly up and down the tank, the fourth just lies around.
Mine don't seem to be nocturnal as they are swimming all day.
What I am wondering now is are they upset that two more were added or perhaps trying to harm each other, including the one that lies around?
The other two never did this, as said, the three are swimming up and down really fast and they do this until they tire.
I read up on something about catfish and that they get confused but didn't understand it all.....I don't know if my two catfish are called catfish, mine are bottom feeders and maybe an inch long max.
Any help would be appreciated, they were added to the tank just yesterday, if they were just getting to know each other or were out of sorts and confused, this should have topped.
huss - 2011-04-22 The 2 fish you saw swimming up and down the tank might have a been a act of mating. Expect to find babies loaches soon!
Jean - 2011-11-09 I've seen behavior like this called a "rain dance". I'm sure it's attributed their mating being brought on by rainfall like other fish in their native region if this is correct then a waterfall style filter may be simulating rainfall and bring on this behavior. I have had kuhlis for a few months now and I recently added 4 more bringing a total of 9. They are active all day long and exhibit his behavior as well as far as I can tell it's harmless. They won't breed until they reach sexual maturity which can take as long as 2 years but usually is around 18 months. In large numbers they like to lay around each other in the open all day and often play with each other. Don't worry if your kuhlis are acting like everyone else's their behavior has a lot of contributing factors including other fish in the tank, cover and filtration. The more hiding places you give them the more time they will spend out as they feel safer. There isn't a lot of comprehensive info about their behavior and breeding info is scarce. They have some very odd behaviors often being called foolie loaches because they like to stress out their owners by playing dead. Don't be surprised to find them hanging off plants they love to climb. For now I'm trying to document their behaviors and figure out causes. Most people will try and compare their behavior with other fish species but this can't really be done. Fish behavior is diverse for every type. Don't let people scare you by telling you they are under oxygenated I have two air stones running a lot of oxygen and mine still "rain dance". Best I can say is try to figure out what your tank conditions would be replicating in their natural environment and you might be able to figure out their seasonal behavior patterns. I'm rambling a bit. Hope I helped.
Soyer Pan - 2014-06-03 Despite good water parameters, triple zeros on the cycling ( 0 ammonia, 0 nitrite, 0 nitrate) in my planted sand ten gal with just six pepper cories, my two new black kuhli loaches kept doing the circles too and got me worried. I knew they school like cories, but more research shows I should get more. Thinking of buying three more. Thanks for sharing. Do you still have yours and how are they doing?