Personal tools
You are here: Home / Articles & Art / Suckerbelly Loaches

Suckerbelly Loaches

by Martin Thoene last modified Dec 10, 2006 01:59 AM
Article by Don Kuhns from 1999. Of interest because it shows how knowledge of these fish has progressed.

From: Don Kuhns (

Date: September 7th, 1999

(Originally part of a thread on the Loach Forum on Butterfly Sucker Loaches)

I have found sucker-belly loaches to be hardy fishes, once their basic requirements are met. In fact, some of my oldest fishes(about five years old) are hillstream loaches. Since my article about these fishes at Aquaria Central seems to be inaccessible, I'm gonna copy the (slightly edited)entire text below. I hope it helps you. ---Don

Suckerbelly Loaches

Whether labeled as "Chinese butterfly plecos", "Borneo suckers", "lizardfish", "flossensaugers", or one of their many other common names, hillstream loaches are definitely a standout among the usual array one would see at the local fish store. With their flattened bodies sticking to the front glass, like some kind of alien flounder, they catch the eye. Look close at some of them, and you can see their little hearts beating. They are a highly unusual fish, and to many aquarists, that equates to highly desirable. It's not surprising they have become a staple of the aquarium trade. An exchange of information about these fishes is long overdue, for though they are small, peaceful and hardy fishes, they are not for every tank.

First let me offer a disclaimer. I do not consider myself a "successful" keeper of hillstream loaches, for reasons I will explain later, or an "expert." However, after keeping them for about ten years, and gaining experience with at least five different species, not to mention reading everything I could get my eyeballs on, I seem to know more about them than most real aquarium experts. I am a hobbyist, and not what many would consider a "serious" one, either. I just really dig these fishes.

"Chinese butterfly plecos" are not plecos, nor are they technically loaches. True plecos belong to the catfish family Loricariidae. There is at least one true loricariid now known as the "butterfly pleco," so I hope this misnomer disappears soon. True loaches belong to the family Cobitidae, but hillstream loaches are a close relation, and I see no problem lumping them in with other "faux loaches" like the Nemacheilus species.

Hillstream loaches are a group of fishes that includes the genera Homaloptera, Gastromyzon, Pseudogastromyzon, and a few other lesser known ones. As the name implies, these fishes come from fast-flowing streams and rivers. There are dozens of species that range throughout most of Southeast Asia. They have adapted to these fast, turbulent waters by developing suction mechanisms in their bellies and fins, and down-turned mouths to graze the algae beds found there. The Gastromyzon and Pseudogastromyzon species have a flattened profile, from which they get the "butterfly" label. The most common one (Gastromyzon borneensis?) ( actually Beaufortia kweichowensis) is tan to dark brown with tiny black spots in random patterns, and black edges to the fins. Homalopterids and others are more slim and cylindrical like typical loaches. Hillstream loaches range in length from 1 1/2 inches to four inches. They are egg layers, and, according to one report, cave spawners. No one has been able to identify male and female sexual characteristics, to my knowledge. Captive spawnings are extremely rare, and all the fishes offered for sale are wild-caught. They are peaceful loners by nature, though the Homalopterids will hang out in the same nooks during the day. The "butterfly" types seem to be the most active, and territorial disputes do arise among them. Their mock battles are amusing. Fortunately, they don't have the equipment to actually hurt each other. In my experience the Homalopterids will rarely come out of hiding during the daytime. Hillstream loaches are fairly hardy fishes. Though they are susceptible to rapid changes in water pH and temperature, they are not prone to disease. I have yet to see one with ich.

Hillstream loaches come from a habitat unlike the ones that most tropical fishes live in. As I mentioned, the hillstreams have strong currents. They are cooler than most tropical waters. The water also has a high level of dissolved oxygen. Algae and "aufwuchs", the tiny organisms that live within it, are a hillstream loach's main source of food. It is because they are accustomed to these conditions that they may be unsuitable for the average tropical fish tank. In fact, a species tank, or a "habitat" tank that contains other coolwater species, such as white cloud minnows, may be the wisest choice for their upkeep.

So what would a proper habitat for hillstream loaches be? I believe the two things necessary for these fishes to thrive are a high level of dissolved oxygen, and a large bed of algae. Hillstream loaches can survive on prepared foods(Tetra tablets seem to be preferred), but my loaches didn't start to look really healthy until I let the algae flourish. Green algae is best, as the fish will consume it along with the critters it harbors. Live and frozen foods, such as blackworms and daphnia, may also be consumed. Like higher plants, green algae requires high levels of light and clean water to prosper. Overstocking or overfeeding your tank with fish will lead to outbreaks of unwanted blackbeard and bluegreen algae. Lots of rocks, and some driftwood, too, not only provide a more natural setting, but provide large areas for algae to proliferate. Plants will also add to the well-being of the tank, though keeping a good balance between plants and algae can be tricky, I have found. Oxygenation of the water can be achieved by typical means, such as photosynthesis, aeration, movement, and agitation.

Also to be considered are the strong currents and water conditions the fishes are accustomed to. The waters are typically soft, and slightly acidic. Temperatures range from 65-75 degrees F. One thing I have wanted to experiment with is the hydrogen peroxide reactor, or "oxydator", which can purportedly increase oxygen to near-saturation levels without increasing the pH of the water. Armed with this device and carbon dioxide injection or peat filtration, one could create conditions very similar to a real Asian hillstream.

Regarding tankmates, hillstream loaches should not be kept with aggressive species. Two of mine were blinded by attacks from larger botias. I have kept them with white clouds, danios, Siamese flying foxes, dojo loaches, Nemacheilus loaches, and the Dwarf loach and Botia striata, without problems.

Now to explain why I do not consider myself a successful keeper of hillstream loaches. To this date, none of my flossensaugers seem to have grown at all. They are plump, active, and appear healthy in every way, but they just don't grow. In fact, I have never heard of anyone's hillstream loaches increasing significantly from the size at which they acquired them. This may be due to the torture these fishes have gone through to reach our homes. I think it's possible that the high temperatures, low oxygen levels, and extreme malnourishment involved in shipping these creatures may have permanently stunted their growth. Look closely at the ones in your local fish store. They are usually gaunt and pale, quite often near death. I asked a fish store employee once what they were being fed. She replied, "Oh, we don't feed them, they're in and out of here so fast." The other explanation is that I just haven't found the right combination of conditions for these fishes to promote their growth. If anyone knows the magic ingredient for this, please e-mail me at Also, if anyone has a question that I haven't addressed, or would just like to have a discussion, please contact me. I am eager to learn about others' experiences with these fascinating fishes.

Don Kuhns ---May 16, 1999


"Collector's Edition - Catfish and Loaches: the Bottom Dwellers"
Published by Tetra Press, West Germany.

"Aquarium Atlas"
Published by MERGUS-Verlag Hans A. Baensch, 1986.

Special thanks to Jeff Shafer at Loaches Online

Document Actions