A New Look At Loaches
By Neale Monks
( click images for full size picture )
Loaches have become steadily more popular in recent years, and more species are available now than ever before. Some can make excellent community tank residents, but others are challenging fish that demand special care. Because these fish are so new to the hobby, reliable information on their needs can be hard to obtain. In this article we’ll look at these new loaches, and what they need to thrive.
Most of the new loach species come from South and Southeast Asia, in particular Burma, Vietnam and China. With few exceptions, they come from fast-flowing streams, often in upland areas, so compared with the well established species like clown loaches and kuhli loaches, these new loaches prefer relatively cool, well-oxygenated water.
Acanthocobitis botia is one of many new loaches on the market currently being exported from South and Southeast Asia
Does this limit their usefulness as community fish? Not really; most of the fish that enjoy fast-flowing water also like moderate temperatures and lots of oxygen as well. So these loaches would make fine companions for things like barbs, danios, hillstream trout, Corydoras catfish and other fish that inhabit streams and shallow rivers.
The fish we call loaches potentially come from several different families. Most come from what we might call the true loach family, the Cobitidae. Among the principal genera that yield species to the aquarium trade are Acantopsis (the horseface loaches); Botia (the South Asian botias); Chromobotia (the clown loach); Misgurnus (the weather loaches); Pangio (the kuhli loaches); Sinibotia (the subtropical Chinese loaches); Syncrossus (the tiger loaches); and Yasuhikotakia (the Mekong loaches). At this point it’s worth mentioning that loach taxonomy has been substantially revised since in the last few years, and many of the loaches that were once placed in the genus Botia have now been split off into separate genera, including Chromobotia, Sinibotia, Syncrossus and Yasuhikotakia.
Balitoridae. Compared to the Cobitidae, many members of this family show particular adaptations to life in fast-flowing water, for example sucker-like pectoral and pelvic fins. Among the genera encountered in the aquarium trade are Acanthocobitis, Beaufortia, Gastromyzon, Homaloptera, Nemacheilus, Pseudogastromyzon, Schistura, Sewellia, Sinogastromyzon, Vaillantella and Yunnanilus. Some of these have been around for a while, usually sold as Hong Kong Plecos, Borneo Suckers or Butterfly Loaches, including species of Beaufortia, Gastromyzon, Pseudogastromyzon, Sewellia and Sinogastromyzon. Without exception, these Hong Kong Plecos come from cool, fast-flowing habitats are rarely adapt well to the average community tank. In fact all the Balitoridae do best in clean aquaria with plenty of water current and lots of oxygen.
Garra cambodgiensis is more closely related to the minnows and carps than the true loaches, despite often being sold as a loach.
The third family from which loaches are derived is the Cyprinidae or carp family. Most members of this group are midwater fish, notably things like minnows and barbs, but the genus Garra in particular includes species that have become distinctly loach-like in appearance, and often get sold as stonelapping loaches. There are numerous Garra species in the trade, including at least one species, Garra rufa, that has become famous outside fishkeeping circles as the “doctor fish” for its supposed ability to reduce the symptoms of certain skin diseases. People with psoriasis bathe in pools filled with these fish, and the fish nibble away at the dead skin.
One issue with loaches that needs to be considered is their social behaviour. These are usually boisterous fish, and while they may form schools in the wild, under aquarium conditions individual fish can become territorial bullies. Depending on the species they are either best kept as singletons or else in fairly large groups of at least six specimens. There are exceptions though, with most species of Acanthocobitis, Garra and Pangio being reasonably to very peaceful. These are consequently among the best loaches for community tanks. The Hong Kong Plecos are completely peaceful towards their tankmates, though they are territorial and can be feisty amongst themselves. Still, being relatively small, it isn’t difficult to provide enough space for a group of Hong Kong Plecos to settle down nicely.
By contrast, species of Botia, Schistura and Syncrossus tend to be much more boisterous. At feeding time they will often monopolise food, excluding more delicate fish such as Corydoras. Some of these loaches go beyond being merely boisterous and are actually quite aggressive animals, and their tankmates should be chose with care.
Loaches can be divided into two main types, those that feed mostly on algae, and those that feed mostly on benthic invertebrates such as worms, snails and insect larvae. In terms of feeding, all you need to do is identify the type of loach you’re keeping, and provide the right balance of algae and invertebrates in their diet.
Hong Kong Plecos for example feed mostly on algae, and in the aquarium will do best if there is plenty of green algae for them to graze on. Failing that, algae wafers make a good alternative. Their diet can be supplemented with bloodworms, tubifex and so on, but it’s important not to think of these fish as scavengers. They’re not scavengers, and if you don’t put green foods out specifically for them, they’ll starve.
Garra are somewhat similar to Hong Kong Plecos, but a bit more omnivorous. So alongside algae wafers, they also enjoy meaty foods, like chopped seafood and catfish pellets.
Most of the remaining loaches are highly omnivorous, consuming whatever they can find. Again, they shouldn’t be treated merely as scavengers, but given a varied diet of algae wafers, cooked peas, chopped seafood, frozen bloodworms, earthworms, snails and the like, these loaches should do well.
There are a few key things to remember when keeping loaches. The first is that these are fish from fast-flowing streams, so above all else, they need clean, well-oxygenated water. Generally this means a robust filtration system. Look for a filter system that provides 8-10 times the volume of the tank in turnover per hour, and possibly more where Hong Kong Plecos and most of the other Balitoridae are concerned. An external canister filter with a spray bar at one end is probably the easiest way to create the conditions most loaches prefer.
Water quality needs to be excellent; none of these loaches tolerate ammonia or nitrite for long, and a few species are also intolerant of nitrate as well. Water chemistry is relatively unimportant, provided you avoid extremes; pH 6-8, 5-20 degrees dH should suit most species well.
Like most loaches, Clown Loaches needs clean, well-oxygenated water and do best in a spacious tank with lots of water current.
Temperature will need be set at a level appropriate for the species being kept. Very few loaches do well above 25 C (77 F) and most will need to be kept between 20-24 C (68-75 F). The Hong Kong Plecos will prefer water even cooler than this, around 18-20 C (64-68 F) being about right.
Loaches are burrowing fish, and you’ll see them at their best in a tank with a soft sand substrate and round, water-worn boulders. When choosing a substrate, look for one known to be safe with burrowing fish. Lime-free substrates should be used to prevent problems with pH and hardness. An inexpensive option is silver sand (smooth silica sand) sold in garden centres. Some of the fancy sands sold for use in planted tanks are not appropriate for use with burrowing because they are so abrasive; Tahitian Moon Sand for example should not be used with loaches.
These loaches are fairly small and somewhat eel-like in shape, and only a few species turn up in the aquarium trade with any regularity, notably the Zipper Loach Acanthocobitis botia (11 cm/4.5 inches) and the Cherry-Fin Loach Acanthocobitis rubidipinnis (8 cm/3 inches).
The Cherry Fin Loach Acanthocobitis rubidipinnis is a useful species for the community tank.
The Zipper Loach is marked with irregular dark bands across a yellowy body. It has distinctive markings on its tailfin including a black eyespot and v-shaped chevrons; presumably, these make the tail look more like the head, so that predators can’t predict which way this fish will swim when alarmed.
As its name suggests, the Cherry-Fin Loach has red fins; those on the males are very red indeed, while those on the females are somewhat fainter and more orangey.
Numerous species were lumped into the genus Botia at one time, including species such as the Dwarf Chain Loach, now Yasuhikotakia sidthimunki; the Clown Loach, now Chromobotia macracanthus; and the Skunk Loach, Yasuhikotakia morleti.
The Emperor Loach Botia udomritthiruji gets fairly larger but mixes well with robust midwater fish of similar size.
Maintenance is generally not too difficult. Soft, slightly acidic water is preferred, and most species do well across the normal range of tropical aquarium temperatures, with around 25 C (77 F) being ideal. They are burrowing fish, so as is often the case with loaches, they do best in tanks with a soft substrate. They are completely omnivorous, and will consume a variety of foods including algae wafers, bloodworms, catfish pellets, etc.
The Gold-Silver Loach (Botia histrionica), Twin-Banded Loach (Botia rostrata) and Emperor Loach (Botia udomritthiruji) are all pretty similar in appearance, with brown bands on a golden body, but the Emperor Loach is perhaps the most beautiful and certainly commands premium prices. At 12-15 cm (5-6 inches) in length when mature, these three loach species are fairly robust, and though placid enough towards midwater tankmates, they are very boisterous at feeding time.
At first glance, many Garra could be mistaken for fish such as Flying Foxes (Epalzeorhynchos kalopterus) and Siamese Algae Eaters (Crossocheilus siamensis). They are indeed relatively closely related to those fish, all of them belonging to the carp family Cyprinidae. They have a wide distribution, with species being found in Africa and across Eurasia from Turkey to China.
Garra flavatra are sociable algae-eating fish, popular because of their small size and generally peaceful behaviour.
Differences in size and colour apart, they’re all fairly similar in terms of care. Some species are a bit more boisterous than others, but all do best kept in reasonably large groups. Some of the larger species can be kept as singletons, but these fish will be more territorial kept that way, and also somewhat shy.
Probably the most commonly traded Garra is the Panda Garra Garra flavatra. It is one of the smallest species and consequently the most easiest to keep in groups of six or more specimens. It is noted for its lovely colouration: black and yellow banding on the body, and fins that are either orange or red. They are superb algae eaters and work very well in community tanks. They do expect water with lots of current and plenty of oxygen, but apart from that, these are undemanding fish that adapt well to a broad temperature range.
Genus: Gastromyzon, Pseudogastromyzon and Sewellia
Though commonly called Hong Kong Plecos, these fish are in fact loaches. They come from fast-water habitats, and in terms of aquarium care are all fairly demanding. They need very clean water with plenty of oxygen, and the water temperature should be fairly low, ideally 18-20 C (64-68 F). Without exception, these fish are poor choices for the average community tank, despite being widely sold as algae-eating fish. In fact their survival rate in the typical community tank is dismal.
All share the same basic shape, being flattened from top to bottom, and having large, almost circular pectoral and pelvic fins that form a kind a of sucker. They spend most of the time stuck to rocks, darting from one spot to the next. Wild fish feed extensively on aufwuchs, the combination of algae and microscopic animals that encrust rocks in clear waters.
Hillstream loaches such as Sewellia lineolata are not community fish, and need very particular conditions to do well.
In the aquarium these fish are finicky feeders that will need algae or algae wafers to do well. They are mildly territorial, but being relatively small fish, typically no more than 5 cm/2.5 inches long, keeping multiple specimens is not difficult. Indeed, when kept in groups they are far more outgoing, and the aquarist will enjoy watching them scoot about, chasing one another off favoured feeding spots.
The Gold Ring Butterfly Loach Sewellia lineolata is typical of the group. Kept in a fairly cool aquarium with plenty of water current it does well, and can be easily mixed with species from similar habitats such as White Cloud Mountain Minnows and Danios. Water chemistry isn’t critical, but avoid extremes.
These are the Kuhli Loaches, probably the best loaches for the community tank, and certainly the best choice for someone after an eel-shaped fish. On the other hand, they aren’t the easiest fish to maintain, and many specimens are lost through ignorance of their basic needs.
For a start, these are gregarious fish; they must be kept in groups! Buy at least five specimens, and preferably more than that. They’re also nocturnal fish, so won’t be happy in a tank without hiding places. Kuhli Loaches like to burrow, and they adore hollow ornaments and other such caves, so create a habitat for them with soft sand and plenty of shade. Once settled in, you’re much more likely to see these fish if they feel secure.
Pangio “panda” is not a commonly traded Kuhli Loach, but maintenance is much like any of the others.
Kuhli Loaches are omnivores, but all too often they’re added to the tank as scavengers. Kept this way, they soon starve to death. Instead, leave bloodworms and other small meaty items out for them. Don’t force them to compete with other bottom feeders; ideally, choose Kuhli Loaches or catfish, rather than both!
There are numerous species in the trade, and you’ll rarely find them correctly identified. Mostly the ones seen are the chocolate-and-orange banded species such as Pangio kuhlii and Pangio myersi. Only exceptionally will oddball species such as Pangio “panda” be sold. There isn’t much variation in the group when it comes to size, with most species getting to around 8-10 cm (3-4 inches) in length, the females being bigger and more deep bodies than the males.
In general terms, Schistura should be maintained very much like the Hong Kong Plecos (Gastromyzon, Pseudogastromyzon and Sewellia) mentioned above. They need an aquarium with plenty of water current, but temperature is less critical, and they do well at middling temperatures around 25 C (77 F).
Schistura are omnivorous fish; in the wild they burrow through the sand looking for worms, insect larvae and other small animals. In the aquarium they will eat most foods, but frozen bloodworms and tubifex worms are particular favourites.
Schistura are fairly small, getting to about 10 cm (4 inches) in length, but they’re strikingly marked fish in many cases, and that’s ensured that they’ve quickly become popular fish. Depending on the species, they are marked with bright red, orange and yellow bands around the body as well as attractively marked fins.
The Sumo Loach Schistura cf. balteata is not easy to keep, and not recommended for community tanks.
On the downside, these are among the most territorial loaches, and while they won’t harm midwater fish, they will chase one another about enthusiastically. They can be shy though, so the aquarium will need to including hiding places as well as swimming space. A school of suitable dither fish, such as danios or small barbs, will also encourage these fish to swim about.
There are several species in the trade, including some species that haven’t yet received formal scientific names. Among the species traded are the Three-Banded Sumo Loach (Schistura balteata), the Sumo Loach (Schistura cf. balteata), and the Crimson Loach (Schistura sp. “Crimson”). Apart from differences in colouration, care is similar for all these species.
These are the Tiger Loaches, a group that includes species that can get to as much as 30 cm (12 inches) in length. They’re also among the most belligerent, and so are not really suitable for the community tank. Perhaps surprisingly given how boisterous they are, these fish also need to be kept in groups of at least six specimens. In smaller groups they will pick on one another, the weaker specimens getting bullied, and when kept singly they become very shy.
The big Syncrossus species like this Syncrossus berdmorei are attractive fish, but very demanding because of their size, personality, and need for good water quality.
Because of their size and social behaviour, these are difficult fish to recommend to most aquarists. But they aren’t especially demanding in other respects, all these fish doing well at normal tropical aquarium temperatures and adapting to a range of water chemistry conditions. They are total omnivores, eating anything they can find, but with a particular liking for robust invertebrate foods such as shrimps, snails and earthworms. Otherwise they thrive on the usual mixed diet of algae wafers, catfish pellets and frozen foods.
This genus of very elongate loaches contains species rather similar to the Kuhli Loaches in terms of care. Wild fish slither about in leaf litter looking for the tiny prey animals they consume, predominantly insect larvae and small crustaceans. In the aquarium they are omnivorous, but like Kuhli Loaches won’t do well if forced to compete with more aggressive fish at feeding time. In one regard they differ from Kuhli Loaches quite markedly: these are territorial rather than gregarious fish, and shouldn’t be crowded.
Fork-Tailed Loaches such as Vaillantella cinnamomea are delicate, and will only thrive in quiet, well-maintained aquaria.
The most commonly traded species is the Fork-Tailed Loach Vaillantella maassi, a species that gets to about 15 cm (6 inches) in length. It has a reddish-brown body marked with a bright orange band running along the dorsal surface from nose to tail. As its name suggests, it’s tail fin is deeply forked, and an easy target for nippy fish such as tiger barbs and serpae tetras. Its colours are quite striking, but do depend on the health of the fish and in particular how well it is being fed. Crustaceans in particular will help bring out its orange colouration. The Brown Fork-Tailed Loach Vaillantella cinnamomea is similar but lacks the orange band. While less colourful, it seems to get traded quite commonly.
Many of the species once called Botia by aquarists now belong to this genus, including the Blue Botia Yasuhikotakia modesta; the Skunk Loach Yasuhikotakia morleti; and the Dwarf Chain Loach Yasuhikotakia sidthimunki.
In terms of aquarium suitability they’re a bit of a mixed bag; some species are relatively peaceful, while others are unacceptably aggressive. The Dwarf Chain Loach is a pretty good community tank resident. It is highly gregarious, and at a mere 6.5 cm (2.5 inches) in length, there’s no excuse to keep fewer than six specimens. Ideally, they should be kept in bigger groups, a dozen or more, and kept properly these loaches will flutter about in midwater as often as they cruise along the bottom, and best of all, they’re active during the day! These are highly entertaining fish that thrive at standard tropical temperatures and will adapt to most water chemistry conditions provided extremes are avoided.
Dwarf Chain Loaches Yasuhikotakia sidthimunki must be kept in large groups.
The Blue Botia is a middling species in terms of temperament, being gregarious but boisterous, and best kept with robust, midwater fish. It’s a fairly large fish, wild specimens getting to well over 20 cm (8 inches) in length, though aquarium specimens are generally a bit smaller.
The Skunk Loach isn’t terribly big, getting to about 10 cm (4 inches) when full grown, but it is remarkably feisty and prone to bullying its tankmates. It is another gregarious species that should be kept in groups of 5 or more specimens. This is one of the most widely traded loaches, presumably because of its very attractive colouration, pink with a black, skunk-like band running from nose to tail along the back. But it is a poor choice for the community tank, and best kept in a single species aquarium or with larger, equally robust midwater fish.
Many of these new loaches are now regular features in the larger aquarium shops, and while some command high prices, others are more affordable. But it has to be said that this isn’t an “easy” group of fish, and there are plenty of species that would make very bad choices for the average community tank. Always take care to identify a loach prior to purchase, and double check its requirements before you spend any money. Choose the right species though, and loaches add a certain charm to the bottom of an aquarium that catfish simply don’t: they’re inquisitive, lively animals with cute whiskers and often rather bright colours. Just be sure and shop for your loaches carefully!
Loaches Online is the key web site for aquarists interested in keeping loaches.