All About Botia Loaches

Learn about the nine popular species of Botia loaches to look for in your local fish store.

Dwarf chain loach (Yasuhikotakia sidthimunki). Photo by Al Castro

The botia loaches are some of the most popular aquarium fishes — and for well-deserved reasons. Ranging in size from the tiny to the very large, there are members suitable for any size of aquarium. They are all interestingly patterned and often brightly colored, and they live at the bottom of the aquarium. Many are well-mannered in the community aquarium, while others are able to hold their own in aquariums with more aggressive tankmates. Many species display odd and unusual — humorous even — behaviors. And best of all, they eat snails.

The botia loaches are active bottom-dwelling fishes found in Asia, where some of the larger species are used as food fish. They fill the same niche as our North American suckers do, rooting about in aquatic plants and along the bottoms of bodies of water for insect larvae and similar food items.
Loaches bear a striking but superficial resemblance to catfish, but in fact they have more in common with zebra danios, which belong to the same order as the loaches. They are also closely related to the so-called freshwater sharks (e.g., Labeo spp.).

Previously, pretty much all of the commonly encountered botia loaches were in the genus Botia. Recent (2004) revision to the genus has restricted it to only a baker’s dozen of species, with essentially all of the species familiar in the hobby moved to other genera. The botias are in the family Cobitidae, which contains all of the familiar loaches. There are two subfamilies of Cobitidae, Cobitinae and Botiinae, which means it’s more correct to refer to these loaches as Botiinae or botine loaches — not botia. There is a handful of species typically found in fast-moving water contained in the closely related family Balitoridae, including the hill stream loaches (Gastromyzon spp.). The Botiinae tribe contains seven genera of loaches, all of which are fairly similar to the popular clown loach.

Loach Characteristics

The Botiinae loaches are famous for their snail-eating abilities. These fish have an uncanny ability to root the escargot from even the tiniest — or surprisingly largest — shells. They can depopulate an aquarium infested with snails in a matter of days. They are also infamous for a slightly more dangerous reason. Botiinae loaches have a small spine located beneath each eye, which can flick out like a switchblade (the original genus name Botia is derived from an Asian word meaning “warrior”). These spines are incredibly sharp and deter predators, as well as shred nets. I once had a large Yasuhukotia modesta jump out of the aquarium. Instinctively, I simply reached down and grabbed it. One of the fish’s “switchblades” left a cut in my palm from thumb to pinky. Botiinae loaches should be carefully herded into plastic containers when moved and always double-bagged.

The Botiinae loaches also lack scales, which makes them difficult to medicate. Medicines for ich and many other fish diseases are quite hard on scaleless fish and will kill them. Treatment with alternative remedies (e.g., increased temperature for ich) or medicines specifically intended for scaleless fish are a must. Because they lack scales, they are quite susceptible to injury. All loaches like to dig and root through the substrate, and when in aquariums with coarse gravel or sand, they may injure themselves doing so. Loaches do best when maintained in aquaria with fine sand or other “softer” media. Keep in mind that loaches are cyprinids, and like most cyprinids, they are schooling fish. Kept individually, they will typically hide and eventually wilt away. All species of loaches should be kept in a group of at least six.

Popular Loaches

Bengal queen loach (Botia dario). This is a striking striped fish that is sometimes seen in the hobby, though it often commands a high price. They demand high oxygen levels in the aquarium and also require a large school — forget a half dozen and shoot for a full dozen. They can reach 6 inches or so in aquaria.

Burmese loach (B. histrionica). The Burmese loach is a playful fish with a species name that shows just how fun they can be in the aquarium (“histrionic” means dramatic or theatrical). They look like a pale version of a clown loach or perhaps a clown loach crossed with a polka-dot loach. Their pattern is striking and beautiful. They are quite peaceful and great community fish when kept in good numbers. Unfortunately, they can be somewhat expensive, but they are well worth the price.

Polka-dot loach (Botia kubotai). The fish that started all the name game problems is the polka-dot loach. It looks quite a bit like a grown-up version of the dwarf chain loach. It is essentially black with yellow dots on it, though the black networking may be thin enough in some individuals to call it yellow with black networking. Polka-dots are extremely active, and they will play nonstop in a group. They are a smaller loach, reaching only about 3 to 4 inches.

Yo-yo loach (B. lohachata). The most commonly encountered botia is the yo-yo loach. Individuals have a pattern of black lines forming the letters “Y” and “O” over and over again on their bodies, hence the name. They are often confused with the very similar B. almorhae, and the two are sometimes considered synonyms. They will school together, so from the aquarist’s point of view, the difference doesn’t really matter. Botia almorhae gets slightly bigger (6 inches) than B. lohachata (5 inches). Both are quite peaceful and relatively forgiving of water conditions.

Striped loach (B. striata). The striped loach has numerous stripes running along its body, giving it a zebralike appearance (another common name). This is an excellent community fish, being quite a bit less aggressive than other species. It reaches 3 to 4 inches in length, and in some individuals, the stripes may form an almost mazelike pattern. These are great snail-eaters and a fantastic alternative to the clown loach.

Clown loach (Chromobotia macracanthus). Undoubtedly, the best-known loach is the clown loach. The genus Chromobotia is monotypic, meaning that the clown loach is the only species in the genus. Clown loaches can be found at virtually every aquarium store, often for sale at only 1 or 2 inches in length. They are an orange-beige with three jet black stripes on either side and bright red fins. Their name comes from their behavior, not their coloration — they will “clown around” in the aquarium, often laying down, playing dead or otherwise being weird. Unfortunately, clown loaches are rather a poor choice for the average community aquarium. As they grow, they can become somewhat aggressive with other fish, and they do grow large. Clown loaches mature at about 8 inches and will easily reach a foot in aquaria.

Red-finned loach (Yasuhikotakia modesta). Another unfortunate side effect of many species of fish being dyed bright colors is that many aquarists see a brightly colored fish and assume it has been dyed — I once overheard two customers swearing to another that neon tetras were injected with dye. One fish that looks like it has been dyed is the red-finned loach. I’ve always been curious about the species name because “modest” does not describe this fish. The fins are bright red, while the body is an incredible dark blue. They are gorgeous fish. Unfortunately, some of these individuals are soaked in dye to deepen the blue, and sometimes they show up in purple, green or other colors. This dye fades in a few months, and you’re still left with a pretty blue fish.

The red-finned loach, like the clown loach, gets quite large, with individuals reaching a maximum size of about 8 to 12 inches. They can be quite pugnacious, which makes finding tankmates difficult. Less aggressive cichlids, large gouramis and barbs mix well with these fish, as do other loach species. They tend to dig a bit more than other loach species, and in aquariums with rough gravel, they may often have damaged snouts, which can lead to infection and death.

Skunk loach (Y. morleti). The skunk loach is one of my favorite loaches. The back color ranges from a pale pink to almost orange, with a jet black stripe running from nose to tail along the back. Like other loaches, they do best in a group of at least a half dozen. They tend to be a little more secretive and often hide in the most amazing spots, finding niches in driftwood, rocks and other material. They are also a bit aggressive and mix well with other somewhat-nippy fish, such as tiger barbs, larger gouramis and fairly passive cichlids (e.g., Thorichthys meeki, Archocentrus sajica, etc.).

Dwarf chain loach (Y. sidthimunki). The genus Yasuhikotakia contains many of our familiar old loaches. The genus is named in honor of Yasuhiko Taki, Ph.D., a Japanese fish ichthyologist. The best-known member of this new genus is the dwarf chain or monkey loach (Yasuhikotakia sidthimunki), a new contender for best fish-related tongue twister. These are the smallest loaches, with individuals often seen at less than an inch. They reach a maximum size of perhaps 2 inches. They are a pale yellow with a chain-link pattern on them.

They bear a striking resemblance to Y. nigrolineata, which is sometimes imported and sold under the same name, though the latter is far darker than the dwarf chain loach. Both of these are schooling fish that will often swim in midwater. They are small, extremely peaceful fish, and they are great snail-eaters — an ideal fish for a small planted aquarium. Keep them in groups of at least six.

In the wild, both clown and dwarf chain loaches are critically endangered. However, they appear to be bred in the Far East using hormone treatments. Several aquarists have reported that large groups (several dozen fish) will spawn in home aquaria (Duffil, Mark. 2007. “Yasuhikotakia sidthimunki — Spawning Success!” ), though yields are quite low. Obviously, both eggs and fry are quite small and easily picked off by not only the adult loaches, but also by other fish in the aquarium or stray vicious brine shrimp.

The Botiinae loaches form a diverse group. While their nomenclature has recently gotten a bit more confusing (and may be further revised), the loaches are still excellent aquarium fish and great snail-eaters. While some of these loaches are a bit too aggressive for community aquaria, others are perfectly suited. Many of the common loach species are incredibly variable, with patterns differing wildly from the norm. They can be versatile and interesting fish in aquaria and will often display great antics. AFI

Joshua Wiegert is a long-term fishkeeper. His main interest is the conservation of fish and their environments. He currently works with an aquarium maintenance company in the Washington, D.C., area.

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Fish · Freshwater Fish