Loaches: Riverine Acrobats of the Orient, Part 1
Author: Stan Sung
A look at the many beautiful, playful, and intelligent loach species available in the hobby, with a discussion of their differing degrees of suitability for the home aquarium.
Traveling Down the Ayeyarwady River
We followed the muddy stream through a forested gully as it snaked its way around ruined pagodas from the Eleventh Century. The afternoon sun warmed the crumbling sandstone temples as long, dark shadows crept up the ancient carved facades. The stream eventually fed into the mighty Ayeyarwady (Irrawaddy) River in the heart of Myanmar (formerly called Burma). At the mouth of the stream, villagers had set up a crude fish trap. A long, rectangular trough made of netting had bamboo poles staked in the mud to keep it in a U form. The open end of the trap faced upstream toward where the villagers were building a dam that was little more than a barrier of mud. The feeder stream swelled behind this temporary “dam” as it strained to get to the main river channel.
We slumped into the deep sediment up to our calves and pitched in by taking handfuls of mud to help the fishermen build the barrier up higher. Once completed, the feeder stream backed up into a large pond about 20 feet wide and 40 feet long. At once, we dug deep into the mud dam to tear it down. The water poured out of the dammed stream and emptied into the awaiting net with great force. Eels, catfish, gobies, and snails came pouring down into the awaiting net. Best of all, there were loaches, those clowns of the aquatic world, rushing in for capture as well.
Clowns of the Water World
The active, playful cyprinids known collectively as loaches make delightful aquarium residents. From the diminutive members of the group such as the 1½-inch Schistura pridii to the giant, 6-pound predatory Leptobotia elongata, these fish all possess big personalities, whether they are an inch long or 20 inches long! Very few of our captive aquarium fish can be described as “playful.” The vast majority of loaches, however, are social, intelligent creatures that will cavort, chase, and follow one another constantly. Some species of the genera Yasuhikotakia and Chromobotia also have the endearing habit of resting completely on their sides. These chunky fish love to tumble over one another while resting in communal groups. Sometimes they can be found stacked like sardines while at other times one might find them all lying on their flanks against the front glass of the aquarium!
Loaches, except for Nemacheilus species, have bifid (two-pronged) spines below the eyes that are used as weapons during battle. These prongs are placed in a groove under the eye, and when in a fight they are flared out much like a switchblade knife. Handle netted specimens with care and do not pick them up with bare hands. While these personable fish will sometimes school in graceful, cascading pods, others will bicker and chase each other, all while emitting loud, audible clicks thought to be the snapping of the subocular, bifid spines.
I have collected many of the tropical species of loaches in their native haunts. Some, such as Botia histrionica and Syncrosus species, come from the mighty Ayeyarwady River, or from the surrounding feeder streams. Others, such as Lepidocephalichthys berdmorei, make do with murky rice-paddy habitats that bake in the tropical heat all day. Although we found L. berdmorei dwelling in clay-like mud along the banks of Lake Inle, they really do prefer the rushing brooks leading into the lake. In the unfavorable, sludgy ditches, these and other loaches will adapt by taking oxygen from the water’s surface and passing it through their abdominal tract. The exhalant is then relieved via the anus. In the rice paddies, L. berdmorei cohabitated with snakes, gouramis, and snakeheads. We have scooped up schisturas with a hand net in Southern Thailand, where in the clear-flowing jungle streams they cavort in the rapids along with Danio and Devario species.
Once, in Western Malaysia, we tromped through the primeval forests of Taman Negara National Park, scooping up Acanthocobitis botia from swift, grass-lined streams. Here in Lake Inle, the midwater swimming Yunnanilus brevis lives within a dense, aquatic forest. It seems that there is a species of loach suitable for all captive habitats.
In the Home Aquarium
Many hobbyists have become enchanted with the brook- and stream-dwelling loaches. These interesting charges are at home in clean, well-oxygenated environments, which can be created by utilizing well-placed powerheads and airstones in their enclosures. For most of the other species, almost any aquarium will do, as long as the water and temperatures are within normal ranges and regular partial water changes are performed. Good water quality is important to many species from rivers and streams.
One of the most important factors in the maintenance of most loaches is to have multiple specimens of the same species in the aquarium. These very social fish form a hierarchy in which there is one dominant individual and the aggression is dispersed throughout the community. Members of the genus Yasuhikotakia and Syncrossus can be particularly tough on each other, and it is imperative that enough individuals (a minimum of five or six) be placed into the same aquarium. Aside from the issue of aggression, it really is more enjoyable to have multiple specimens of these social creatures in one tank. If one cannot find or cannot accommodate a group of loaches, then it would be best to purchase only a single individual. If only two or three fishes of the same species are placed together, many times the aggression of the dominant individual may prove to be too stressful for the subordinate fish. This “safety in numbers” is especially true with the more aggressive species such as members of Yasuhikotakia, Syncrossus, Acanthocobitis, Schistura, and some Nemacheilus.
Since most loach fanatics keep their loaches in multiple-specimen communities, it is quite surprising how seldom they breed in captivity. Some, such as the popular clown loach Chromobotia macracanthus, have only been bred a handful of times in the home aquarium. There have been sporadic, unconfirmed reports of the clown loach having been “accidentally” spawned only when the surprised aquarist finds fry during routine tank maintenance. Several representatives of the genera Nemacheilus and Lepidocephalus have been bred and documented in the hobby. Some of the most popular species, such as the blue botia Yasuhikotakia modesta, have never been spawned in aquaria. This is particularly surprising considering the huge numbers of these fishes represented in the trade. The breeding of Yasuhikotakia and Botia is a challenge even for the most advanced of aquarists.
Although most loaches lose their initial shyness in captivity, they will appreciate shelter in the form of rocks, submersed wood, and tough-leaved live or synthetic plants. Some species are light-sensitive and will cower in the shadows for much of the day.
The aquarium substrate is also something to consider. This group of fishes has a set of three or four barbels that are covered with taste receptors. Loach enthusiasts will often keep their subjects in aquariums containing very fine-grained sand, thus protecting the delicate barbels as they search the substrate for food. Large, sharp gravel should be avoided in an aquarium containing loaches.
Feeding is generally a straightforward affair. Most species will take all prepared aquarium foods. Flakes, sinking pellets, tablets, and “wet foods” such as frozen mysis, brine shrimp, daphnia, worms, and cyclops are all taken with gusto. Larger specimens will also greedily gobble up krill and market shrimp. Vegetables in the form of green flakes and table veggies such as zucchini are also consumed by most species. Loaches are often touted as the ultimate in natural snail eradication. My friend Ross Freeman has noted that while some newly introduced loaches (Botia almorhae, Syncrossus sp.) initially consume snails with gusto, they eventually become spoiled by prepared aquarium foods and will soon pass up snails for more easily eaten fare!
Occasionally the hobbyist will run across sickly individuals that will waste away, no matter the amount of TLC that has been offered to it. This is particularly true with Botia species that are collected and imported at too small a size (under 2 inches). Their wasting away is sad to see, especially in fishes as intelligent as loaches. Presumably, some have internal parasites causing the fish to lose weight. I have seen many loaches with an “anorexic” appearance offered in retail stores. These drastically underweight specimens are probably fishes that have been fed sparsely on a poor diet. If the individual is not too young, and has not been overly malnourished, it is sometimes possible to take these emaciated patients home to a quarantine aquarium and nurse them back to health. This is especially true with the more robust representatives of the Yasuhikotakia group.
On the other hand, some species of aquarium loaches are prone to overeating. This is particularly true with the smaller representatives of the genera Schistura, Nemacheilus and Tuberoschistura. Once thin, newly imported fish are of average or above average weight, the feedings of live worms, bloodworms, and mysis shrimp should be monitored to prevent gluttony that can lead to a fatal bloat syndrome. I try to supplement such high protein offerings in conjunction with frozen Spirulina cubes, Spirulina flakes, and veggie wafers.
I have witnessed newly imported Yasuhikotakia modesta performing cleaning duties on willing tankmates, similar to the marine cleaner wrasses. Large labeos (in this case wild Labeo calbasu) remained motionless, with fins erect, as the loaches gently searched their bodies for tidbits. Once the Y. modesta became well fed and acclimated to aquarium life, this cleaning behavior never showed up again. Perhaps in nature some species of loaches will clean other fish of parasites when nourishment is scarce. Other aquarists have seen this cleaning behavior exhibited by kuhli loaches Pangio sp. searching discus for parasites!
I like to keep things geographically correct whenever possible in my own display aquariums. Some people view this practice as being limiting and confining. Other hobbyists, on the other hand, would frown upon any setup that is not a species-only aquarium. Since most loaches only inhabit the bottom of the aquarium, there is a vast assortment of fishes to choose from that are suitable and somewhat geographically correct tank inhabitants.
For the larger representatives of Chromobotia, Syncrossus, and Botia, the medium and large barbs make wonderful roommates. Puntius arulius, P. denisonii, and P. filamentosus are all medium-sized (plus or minus 5 inches maximum) and are brilliantly colored, superb show fish for an Indian biotope aquarium. The flashy barbs will roam in the mid and upper water strata while the loaches can dominate the lower regions.
Great tankmates for the smaller Schistura, Nemacheilus, and more placid members of Yasuhikotakia (sidthimunki and nigrolineata) are small barbs such as Puntius titteya, P. nigrofasciatus, Chela species and Danio species. Reserve non-aggressive, non-nippy fish for the gentle eel-like loaches and tiny species like Barbucca diabolica and Schistura pridii. Representatives of the genera Dario, Colisa (lalia and chuna), and the smaller Rasbora and Microrasbora species will coexist swimmingly well together.
One of the great things about most loaches is that they are adaptable and make suitable tankmates for almost all types of fish. Besides similar species fighting, I have rarely had problems with my loaches living with other species. The only example of extra-specific fighting I have had recently is when some of my gobies (Stiphodon species) absolutely abhorred the introduction of crimson loaches into their quarters. Squabbles led to flying sand, but little in the way of physical damage. If one considers the general size and temperament of each species, rarely will there be any serious problems with compatibility.
Aside from wasting away, the only other common affliction to which loaches are particularly susceptible is ich. Thankfully, this can be treated easily with warm water, about 82°F (high water temperature is not recommended for the hillstream and temperate loaches), in conjunction with most retail ich medication. It is important to note that loaches have either no scales, fine scales, or few scales and can be sensitive to many ich treatments. Using most medications at half strength for twice the recommended treatment duration does the trick without stressing the loaches too much.
I have noticed that members of the genera Mesonoemacheilus and Nemacheilus appear to be particularly sensitive to medications, so extreme care should be exercised when treating ich in these species. Any loach keeper should have a bottle of ich medication handy at all times. Clamped fins and dashing against the rocks are usually the initial symptoms in loaches (before the appearance of white dots). Treat at the first sign of these symptoms using the above-recommended treatment and ich will rarely present much of a threat to your loaches. Avoid purchasing very small botias that are listless, underweight, or holding clamped fins.
Sometimes strange, internal afflictions cause a curvature of the body in many of the Acanthocobitis, Misgurnus, Lepidocephalichthys, Pangio, and other species of eel-like loaches. These stricken individuals will sometimes develop raised bumps and contortion of the body muscles, and will hemorrhage internally. Pass up any eel-like loach if the body is not smooth and straight.
All the wild-caught loaches can arrive in rough condition upon importation. Many importers will routinely run a standard prophylactic treatment consisting of antibiotics (nitrofurazone, malachite green, salt, and de-wormer) for freshly arrived fish.
A Site for All Things Loachy
A one-stop location for anything and everything you want to know about loaches can be found at www.loaches.com. Here at this ingenious page, the webmaster has designed a chart for identification, either by scientific name or via illustrations. The illustrations are very useful for visually identifying species, as the species index can be overwhelming due to its sheer size. This site is constantly being updated and it covers such topics as loach care and diseases. There are even a few pictorial articles that document the changes in color patterns in some of the variable botias species. Extensive articles can be found covering aquarium set up and care of the rarely discussed hillstream loach species. Fantastic web design, outstanding photos of both fish and natural habitats, and clear, straightforward, useful information make “loaches online” a mandatory instrument in proper loach care and identification.
Gallery of Species
I have assembled a random sampling of loach species that I have either personally kept or have collected in nature. I have included an aggression scale of 1 to 5 for each loach species, with “1” being inoffensive and gentle, and “5” being highly antagonistic.
Common Name: Redtail loach
Aggression level: 3
Maximum Size: 3 inches
This is a scrappy, snake-like fish that has an amazingly flexible body. Redtails are quick-moving fish that dart and slither among submersed pebbles. These are territorial fish that will playfully chase each other. A single individual should never be kept, as not only would the loach feel uneasy, but also the hobbyist would miss seeing the complex behavior that A. elongates exhibits. This is a hardy species that may be more suitable for beginning hobbyists then the more fragile kuhli Loaches of the genus Pangio.
Acanthocobitis botia and A. rubidipinnis
Common Name: Zipper loach and cherry-fin loach, respectively
Aggression Level: 3 for A. botia; 4 for A. rubidipinnis
Maximum Size: 3 to 5 inches
I have collected these swift-swimming fish in small, clear creeks deep in the forest of Taman Negara National Park in Western Malaysia. The zipper loaches could be scooped up with dipnets in streams no more then 12 inches deep and 24 inches wide. These streams ran through incredibly lush primary forests where sun bears, boars, and pods of Asian elephants roam. Cohabitating with the zipper loaches were other stream-dwelling fish such as Pristolepis grootii, Labiobarbus lineatus, Cirrhinus caudimaculatus, Cyclocheilichthys apogon, and Osteochilus hasseltii.
Zipper loaches make hardy, active fish for the home aquarium. They can be scrappy, and nipped fins are quite common, although damage that is more serious is rare if enough specimens are present in the aquarium. Recently I procured a red-finned Acanthocobitis cf. botia through rare fish extraordinaire Frank Greco. These creatures showed their beautiful colors as they become more adjusted to their environment.
Common Name: Horseface loach
Aggression Level: 1 or 2
Maximum Size: 8 inches
I have collected A. choirorhynchos in Myanmar. These horseface loaches are gentle giants, rarely showing any hostility toward conspecifics or other tank inhabitants. This shy loach will appreciate fine-sand substrate, as they frequently bury themselves with only their elongated faces showing. In nature, I found them in very large, turbid rivers with a mud substrate. In the Ayeyarwady River in Myanmar, I helped native fishermen retrieve a 300-foot seine that yielded many fully grown 8-inch horseface loaches.
In the Ayeyarwady River the horseface loach can be found alongside Tenualosa thibaudeaui, Mystacoleucus argenteus, Chagunius baileyi, puffer fish Tetraodon cutcutia, and catfish Gagata sp. Dredging a seine net through the thick river mud would yield the loaches, as well as eels Mastacembelus alboguttatus and Monopterus albus.
Common Name: Banded scooter loach
Aggression Level: 1
Maximum Size: 2 inches
Here is a colorful rarity that is a joy to observe in captivity. This is a very active species that is not prone to shyness. They will search out food particles by scooting along any submersed object without ever becoming detached from it. They will follow a rock from top to bottom, even swimming sideways or upside down without their bellies ever leaving its surface. This is an extremely peaceful species that should be kept with other gentle tankmates.
Common Name: Yoyo loach, Pakistan loach
Aggression Level: 2; some large individuals, 3
Maximum Size: 6 inches
This is currently one of the most common members of the assemblage found in retail tropical fish shops. Typical of the members of the genus Botia, this loach changes its color pattern dramatically as it matures. When the fish are young they have a black pattern resembling the letters “Y” and “O” running down their flanks. As the fish grows larger, this simple pattern bends and blends until finally, a dark and reticulated fish appears at adulthood. Specimens vary greatly, with some taking on a distinct greenish cast while others develop wonderful markings reminiscent of the rosettes found on a clouded leopard.
Common Name: Queen loach, Bengal loach
Aggression Level: 3
Maximum Size: 8 inches
The stockiest of the botias, B. dario is a common food fish in its native India. Aside from being heavyset, the queen loach is also unusual for the fact that its color pattern does not change drastically as it grows. Juvenile queens look like bumblebees with a clean pattern of dark brown bars over a yellowish body. Adults have less distinct bars, and some individuals develop a beautiful golden yellow coloration.
Common Name: Burmese loach, gold zebra loach
Aggression level: 2 or 3
Maximum size: 5 inches
These are sporadic imports usually found as contaminants in shipments of another Burmese botia, B. kubotai. I have collected startlingly patterned gold and jet-black juveniles of this species in feeder streams that run into the Ayeyarwady River in central Myanmar. Collected alongside B. histrionica are Syncrossus berdmorei; tank gobies Glossogobius giuris; spiny eels Macrognathus siamensis, M. zebrinus, Mastacembelus dayi, and M. alboguttatus; and Asian upside-down cats Mystus leucophasis. Gold zebras are peaceful and playful and are a delight to keep in the home aquarium. The simple, clean black and gold pattern of the juveniles will eventually become dark gray, curvy bands over a silvery white body.
Common Name: Burmese border loach, border loach, angelicus loach, spotted loach
Aggression Level: 1 or 2
Maximum Size: 5 inches
The ornate, strikingly patterned little border loach has set the aquarium world on fire! Not since the classic clown loach has there been a representative of the group that has been this widely accepted in the aquarium trade. The reasons for this enthusiastic reception are numerous. The terrific color pattern and sociable nature of the Burmese border has assured it a place among the most popular of staple aquarium species. In the Three Pagoda Pass area of Myanmar, Burmese border loaches can be collected alongside Garra flavatra, giant barbs Tor tambroides, Datnioides (Coius) microlepis, and hump-headed glassfish Parambassis pulcinella. Burmese borders are extremely variable as juveniles and adults, with no two patterned alike. They like to travel through the aquarium in small groups of three or four, playfully tumbling midwater. This is a strongly recommended first species for the novice loach keeper.
Common Name: Twin banded loach, sergeant major loach, ladder loach
Aggression Level: 1 or 2
Maximum Size: 8 inches
Looking very similar to B. kubotai when young, B. rostrata can be differentiated by the pairs of dark bars spaced apart evenly along the flanks of the fish. It is unfortunate that B. rostrata are often available at very small sizes (around an inch) and are frequently emaciated and weak by the time they reach the retail circuit. These young botias appear to be a little more sensitive to both ich and wasting syndrome then the other botias. Like many smaller fishes, loaches have a fast metabolism and need to eat frequently. It must be very difficult for small specimens of the sergeant major loach to make the long journey from their native waters in India to the United States aquarium trade without their health becoming severely compromised. If you do purchase newly imported, small individuals, I would suggest feedings at least twice daily of high quality “wet” foods. With this frequent feeding regimen, pay close attention to deterioration of the water quality as well. I would assume that the larger individuals of B. rostrata will handle capture and exportation/importation well and be as durable and dependable as the other botia species available.
[Stay tuned for Part 2!]
See the full article on TFH Digital http://www.tfhdigital.com/tfh/200711/#pg104