Butterfly Hillstream Loach Care Guide: Tips for Keeping these Delicate Fish

Butterfly hillstream loach (lat. Beaufortia kweichowensis) is a small and very unusual freshwater fish. Many aquarists think that trey are from catfish family, however this species is from loach family. These loaches are popular among aquarium hobbyists due to their unique characteristics and their ability to thrive in fast-flowing, oxygen-rich setups. If you want to keep it in a tank you’ll have to recreate the conditions like the ones the fish used to have in the wild.

Habitat in the wild

The butterfly hillstream loach, also known as the Chinese hillstream loach or Hong Kong pleco, is a species of freshwater fish belonging to the family Balitoridae. Scientifically known as Beaufortia kweichowensis, this loach is native to fast-flowing streams and rivers in China, particularly in the Guangxi and Guizhou provinces.

Hillstream loach inhabits in Jiangxi river system (West river), in the South of China, main tributary of Zhu Jiang river (Pearl River). This species was described in the upper part of Guizhou province and it’s widely spread in independent region Guangxi and in Guangdong province.

The butterfly hillstream loach inhabits mainly in depthless rivers with fast flow and upstreams highly saturated with oxygen, small tributaries of rivers and streams; zones restricted with crests and sometimes with waterfalls. Bottom substrate is mainly composed of small rocks, sand, gravel and roundstones. In such places there no even streamside vegetation. The water is crystal clear there with small amount of dissolved oxygen.

Such water and sunlight are good for biofilm development which consists of different types of microorganisms and algae. The biofilm covers all stones and rocks surface like a blanket. Hillstream loaches have evolved unique adaptations to their fast-flowing habitats. They have flattened bodies and suckermouths that allow them to cling to rocks and withstand the strong currents. They possess a specialized respiratory system that enables them to extract oxygen from the water’s surface by gulping air.



Hillstream loaches have an elongated and laterally compressed body shape. They have small eyes located towards the top of their head. Their bodies are covered in small, smooth scales, which contribute to their sleek appearance. This streamlined form helps them navigate fast-flowing waters.


Hillstream loaches have distinct fins. Their dorsal fin, located on their back, is long and extends along the length of their body. The ventral fins, located on the underside, are also well-developed. These fins help them maintain stability and maneuver in fast currents.


Hillstream loaches often display a brown or mottled coloration. This camouflaged pattern helps them blend in with the rocky surfaces of their natural habitats. The exact coloration can vary, but it typically consists of shades of brown, tan, and gray.


How big do butterfly hillstream loaches get?

Hillstream loach full size may be up to 3 inches (7.5 centimeters), although in tanks the fish is usually smaller. However, it’s important to note that this is a general size range, and individual loaches may vary slightly in size. Factors such as genetics, diet, and environmental conditions can influence their growth rate. Some hillstream loaches may reach the upper end of the size range, while others may stay closer to the lower end.


How long do hillstream loaches live?

On average, they have a lifespan of around 5-8 years in captivity, although some individuals have been known to live even longer with ideal conditions. Providing them with a suitable environment that closely mimics their natural habitat is important for their well-being and longevity. This includes maintaining clean water, providing appropriate hiding places, and ensuring good oxygenation and water flow in the aquarium.

Scientific NameBeaufortia kweichowensis
Common NamesHillstream loach, Butterfly Hillstream Loach, Chinese hillstream loach
Native HabitatFast-flowing streams and rivers in China
SizeTypically grows up to 3 inches (7.5 centimeters)
Body ShapeElongated and flattened
ColorationBrown or mottled camouflage patterns
MouthSuckermouth with barbels
Respiratory AdaptationAbility to extract oxygen from the water’s surface
BehaviorBottom-dwelling, clinging to rocks
Water RequirementsClean water, well-oxygenated, moderate flow
TemperamentGenerally peaceful, can coexist with other fish
Aquarium SetupSmooth rocks, hiding places, moderate water flow

Difficulties in keeping

This butterfly hillstream loach can be rather enduring provided with an appropriate care. However, it’s not recommended for beginners to keep this fish in a tank, since it’s rather demanding to water purity and temperature due to the absence of scales.

It is the absence of scales that makes hillstream loach very sensitive to different illnesses and drugs.

Care and keeping in a tank

Tank size

To keep 4-5 butterfly hillstream loaches the tank starting from 50 liters capacity will do, however due to the territory-dependent temper of the fish it’s not recommended to keep more than 4 species is such tanks not to make the fish stressed. More fishes can be kept in more spacious tanks, but still not too many – to avoid fights between them. A minimum tank size of 20-30 gallons (75-113 liters) is generally recommended for a small group of hillstream loaches. This size allows for adequate swimming space and provides enough surface area for oxygen exchange.

Hillstream loaches appreciate tanks with longer lengths and widths rather than tall tanks. A longer tank with a larger surface area helps simulate the swift currents they would encounter in their natural habitat. Aim for a tank that is wider than it is tall.

Water parameters

Temperature: the butterfly hillstream loach inhabits in humid, subtropical area where the air temperature is seldom lower than 15,5 °C and it can be significantly higher in summer.

The tank water temperature range 17-24 °C is considered preferable for hillstream loach care. However, the experience shows that the fish is rather good with higher temperature 68°F to 75°F (20 to 23.8 °C) (including 30 °C but not for a long term) at the condition of high water aeration.

Maintaining excellent water quality is crucial for the health of hillstream loaches. Regular water changes, monitoring of water parameters (ammonia, nitrite, nitrate, pH), and the use of a good filtration system are essential.


Hillstream loaches require strong and well-oxygenated water flow. All Beaufortia fishes are inhabitants of fast running rivers with rocky bottom. A tank should reproduce these conditions as fas as possible, since the hillstream loach is very demanding to water purity and high oxygen content in it. The fish rather badly stands organic impurity of the tank water and the presence of coarse dispersion (bottom substrate particles, for example).

In such case it’s also good to raise the intensity of water circulation. Hillstream loaches group are mountain river loaches united by common conditions of inhabitance in the wild, therefore they require strong water filtration in a tank.

Such a filtration and powerful flow imitating violent natural stream can be created by installing a filter or a pump that ideally should be able to pump more than 10 water volumes per hour. Of course, high aeration and flow are desirable in the tank, however some aquarists consider that high flow is necessary only during the adjustment cycle.

Later the fishes can do with common water flow created by the filter or they can even do without the filter provided with sufficient amount of oxygen in the water.

Tank decor

Bottom substrate can be made of gravel, sand or their mixture. Provide a substrate that mimics the rocky riverbeds found in their native habitats. Smooth river rocks or gravel can be used to create a suitable substrate. Additionally, incorporating driftwood, caves, and plants (preferably hardy ones that can tolerate fast currents) can offer hiding places and enrich their environment. Hillstream loaches needs numerous rocky covers therefore it’s obligatory to add flat rocks, pebbles and roundstones, where the fish eagerly feeds by browsing soft algae from them.

The fish isn’t a timid one but it’s better not to keep it in tanks without any decorations or covers – the butterfly hillstream loach will still look for some covers, for example, behind the internal filter or heat controller.

Plants aren’t very necessary in a tank, since the fish doesn’t have them in the wild, but couple of fast growing plants will help you to deal with nitrates and keep water high quality. The most appropriate plants for tanks are different types of Anubias. These plants don’t create any additional covers but necessary for feeding biofilm develops on their leaves.

Hillstream loach shouldn’t be kept in brand new tanks, the owner has to see if the lid is tightly closed – the fishes can climb the glass wall higher than the water level is and escape from the tank. Though regular water renew is necessary, however it’s doesn’t have to be very often and algae should grow on all surfaces except the tank front wall.


It’s algae eater. All Beaufortia spp. in the wild feed on biofilm covering stones and rocks surface. The film consists of green algae, diatomic algae and different microorganisms. When keeping the fish in a tank one has to pay attention that black beard algae won’t be eaten by the fish since they are too rubbery. You can promote the growth of natural algae in the tank by allowing some surfaces to develop a thin layer of algae, or you can offer algae-based sinking pellets or wafers as a supplement.

Different dry feed can be given to butterfly hillstream loach – tablets, flakes with plant additives. As for me, I use several different types of food, and change them from time to time. There are commercially available sinking pellets or wafers formulated specifically for bottom-dwelling herbivorous fish. These foods often contain a mix of plant-based ingredients, algae, and essential nutrients.

Also it’s possible to feed with flakes with high concentration of plant additives (at the condition that they drown), but it’s less comfortable for the fish to eat them – due to the fish mouth pattern doesn’t allow to bolt the feed pieces or to catch it when falling on a tank bottom.

To keep butterfly loach in a good shape it’s necessary to feed it with live or frozen feed – daphnia, cyclops, brine shrimp, small blood worm etc. However, animal protein should be given sparingly as a supplement, as their primary diet should consist of plant matter. In a tank it’s also rather desirable to provide fish with right amount of necessary algae and microorganisms that have to grow on stones and other solid surfaces.

Tank mates

Are butterfly loaches aggressive? Definitely, no.

Butterfly loach shows rather peaceful attitude to its tank mates – it can be kept together with any kind of peaceful fishes (like betta, dwarf gourami or platy fish) of any size including small ones and even juveniles shrimps (cherry shrimp) .

Don’t keep the fish with large raptorial feeders (Jack Dempsey fish, flowerhorn, oscar fish) and goldfish (pearlscale, shubunkin, oranda, veiltail they are more coldwater).

Although hillstream loach is a fast swimmer and it almost can’t be caught by the other fish, but it can become an easy prey since in the wild fish doesn’t develop a habit of running away or hiding in the wild and in the tank it won’t tend to do so.

When being very scared the hillstream loach changes its coloring into very light one with barely seen spots and the angry fish during the fight also becomes lighter in color, but also a very dark line appears along its back and the fins edges become darker.

Raised dorsal and “divaricate” tail mean warning or trowing a scare – when the fish is calm both a fin and a tail are furled. From several fishes kept in a tank, as a rule, there will be a dominating one – the fish larger and stronger than others, capable to find the feed faster and to scare the others off the feed.

Alpha hillstream loach will own the larger territory and will chaise all other trespassing fishes, which will have to divide the space that is left in a tank between them.

Hillstream loach aggression shows only in chasing each other around the tank, but not for a long time. They can’t physically harm each other, but take into account that when there are a lot of fishes, the weaker ones will be always stressed and possibly hungry which can influence their health negatively.

Gender differences: male vs female

Distinguishing between male and female hillstream loaches (Beaufortia kweichowensis) can be challenging, as they do not display any obvious external sexual dimorphism. Unlike some fish species where males may have distinct coloration, fin shapes, or size differences, male and female hillstream loaches generally have similar appearances.

Hillstream loach males have so called “shoulders” – since its pectoral fins are almost normal to the body. The female’s head edges smoothly turn into pectoral fins edge. From top view it can be seen that the female has more bulky body the the male.

In most cases, unless you have a group of hillstream loaches and observe breeding behavior, it may be difficult to determine the sex of individual fish. If your goal is to breed hillstream loaches, providing suitable breeding conditions and allowing them to exhibit their natural behaviors may help you differentiate between males and females based on their interactions.