The kuhli loach is a great species to keep in a fish tank because they’re excellent little cleaner fish, and they play well with other fish and aren’t at all aggressive.
In this article, we’re going to give you the lowdown on how best to look after kuhli loaches in your fish tank or aquarium and give you all the information you need on the species.
We’ll kick things off with a quick summary before moving onto a full care guide, and finishing off with a range of important facts.
The kuhli loach, Latin name Pangio kuhli, is a tropical freshwater fish, and very much an eel-like fish. It is very slender, and sleeps throughout the day to be awake at night. It’s quite a reclusive freshwater fish, and will dart away or bury itself when disturbed.
The kuhli loach originates from the Malay Peninsula and Indonesia, where it can be found in the sandy beds of mountain streams and slow moving rivers. When in fish tanks, it becomes a bottom dweller, spending the majority of its time around the bottom of the tank.
The kuhli loach is also known by several other names, most notably coolie loach, but also slimy loach, giant coolie loach, and leopard loach.
Ok, we’re going to level with you here. Looking after Kuhli loaches is not recommended for beginners. This is because Kuhli loaches are very susceptible to disease. Whereas most fish have hard scales designed to protect them from bacteria and fungi, kuhli loaches don’t have this luxury. What little scales they do have are soft and faint, and this makes it easier for diseases to get into their little bodies.
The minimum recommended tank size for a kuhli loach is relatively small, coming in at just 15 gallons. If, however, you plan on keeping more than one kuhli loach, then we would recommend that you add on another 3 to 5 gallons for each additional fish.
Kuhli loaches will do just fine around other non-aggressive fish, but since kuhli loaches like to spend their time at the bottom of the tank, you may wish for your other fish to be ones that occupy other areas of the tank, closer to the surface. For this reason, kuhli loaches often share their tanks with peaceful species such as tetras and danios and gourmias.
They can also peacefully coexist with other bottom dwellers such as corydoras and red cherry shrimp.
You should avoid them having to share a tank with aggressive or very big fish.
Same Species Tanks
Although they aren’t schooling fish as such, the kuhli loach likes to be around other members of the same species, with 5 being the best number.
When you set up your fish tank for kuhli loaches, you should try your best to replicate their natural habitat. To do this, you will need to set the thermostat to warm temperatures between 73 and 86 degrees Fahrenheit.
Kuhli loaches prefer their waters to be slightly more acidic than other species prefer, with a preferred pH balance between 5.5 and 6.5. And the water hardness rating should be no more than 5.0 dGH.
What To Put In Their Tank
The best thing to put at the bottom of your tank for kuhli loaches is smooth substrates such as fine sand. This is because they love to bury themselves, and jagged gravel could easily cut through their delicate scales.
With regard to tank decorations, smooth pebbles are ok, and they will enjoy having plenty of places to hide. To achieve this, you could keep rocks or driftwood, or manufactured caves, or even some nice plant life, such as peat moss or java ferns.
The most common disease for kuhli loaches is Ich. Ich is caused by parasites and it can spread very quickly around the tank. You can spot when a loach has come down with Ich when you see white spots all over its body. Without adequate treatment, Ich can be fatal for them.
Food & Diet
Thankfully, kuhli loaches are quite easy to please when it comes to feeding time. They are omnivores, which means that they will eat both plant and animal foods. In fact, can eat pretty much anything and will scavenge for anything that falls to the bottom of the waters.
They adore protein-based fish foods, and especially live protein-based foods, including the likes of bloodworm, brine shrimp, tubifex and water fleas. They will also enjoy standard fish food pellets and freeze-dried fish food.
The important thing to remember when feeding them, is that the food has to sink to the bottom of the tank. This is because they will not swim to the surface to feed.
The kuhli loach has an impressive lifespan for a tropical freshwater fish, and while the average lifespan is thought to be about 10 years, they have been known to live for up to 14 years or so.
But it’s important to note, at this point, that their lifespan depends very much on how they are looked after. Poor water quality, stress, and a less than optimal diet can significantly drop their lifespan.
This kuhli loach is shaped somewhat like an eel, but with sides that are slightly compressed. It has 4 pairs of barbels around its mouth and fins that are very small. Its dorsal fin begins at the middle of its body, with the anal fin further behind. Transparent skin covers its eyes.
The body features between 10 and 15 vertical bars which are dark brown to black, and between these bars, the loach is yellow to salmon pink with a light underside.
A kuhli loach is considered to have reached maturity when it reaches a length of about 7cm, which is 2.75 inches. However, they have been known to grow to a length of up to 10 cm or 4 inches in captivity and up to 12.7 cm or 5 inches in the wild.
Behavior & Temperament
As we mentioned in the species summary, the kuhli loach is a somewhat nocturnal creature, which basically means that it likes to be awake during the night rather than during the day. And sleeps in the day rather than through the night.
As for their behavior, on the one hand, they can be quite reclusive. When they are startled, they will rapidly dart away and will even bury themselves in whatever’s at the bottom of the tank.
However, they are also considered to be a social fish. And while they are not necessarily classed as schooling fish, they can often be found in little clusters, and in particular within the company of their own species.
With regard to their eating behavior, the kuhli loaches can be quite the scavenger, trying to eat just about anything that reaches the bottom of the waters. Being such nocturnal creatures, they prefer to do their feeding at night, when they are at their most alert, and this is what they do when in the wild. When being housed in an aquarium, however, they can be trained to feed during the daytime instead.
Kuhli Loaches don’t reach sexual maturity until about two years of age. Luckily they are communal breeders and don’t have to be paired off.
The breeding of kuhli loaches requires certain conditions. If you intend to breed kuhli loaches while in captivity, you will have to provide plenty of good hiding spaces, and ensure that the waters meet the required parameters and conditions, and that the water remains of a consistent nature and quality.
When breeding, the females tend to become larger in size than the males, and you will be able to see their greenish ovaries through their skin before they spawn. Unfortunately, spawning is not easy for kuhli loaches, but when they do spawn, they lay several hundred greenish eggs, which are then laid amongst the roots of floating plants.
Gender differences: male vs. female
To be honest, it can be quite difficult to tell male and female kuhli loach apart. However, when you look very closely, there are some distinguishing characteristics that you can spot…
The upper/dorsal cross-section of the male kuhli loach is more muscular than that of his female counterparts, and their pectoral fins are generally larger and are more paddle-shaped. They also frequently have some kind of pigment in them, too.
- Just below each of their eyes, the kuhli loach has a pair of sharp spines. These are unnoticeable when the fish is relaxed, but the moment the fish feels threatened, they will pop up. It’s a great little defense mechanism, and it really helps to deter would-be predators.
If a kuhli loach was eaten by a predator, these sharp spines are its last line of defense, and will cause the predator harm. It is because of this feature that the kuhli loach earned its scientific name, which is Acanthopthalmus, which means “prickle-eye”.