Frequently asked questions on balitorids


Often seen for sale as Hong Kong plecs or Hillstream loaches, these fish are in fact neither catfishes nor the typical cobitid loaches, as Matt Clarke explains.

What is a balitorid?

Balitorids are members of the family Balitoridae. They are small bottom dwelling freshwater fishes from Asia and there are about 500 species in 37 genera. Gastromyzon are the most widely seen in UK shops.

Are they easy to obtain?

The most common ones are usually seen for sale in the coldwater sections of aquatic shops are usually sold as Hong Kong or Chinese plecs. However, they aren't all from China (most are from Borneo), and they are certainly not plecs - they aren't even catfishes, in fact. Some are sold as hillstream loaches, although they aren't true cobitid loaches either. Balitorids are actually a member of the cyprinid order are cousins of the cobitid loaches.

Are all balitorids similar?

No. The family is big and diverse and there are some notable differences between them.

The balitorines (subfamily Balitorinae), or Chinese plecs are the most commonly seen. These have a flat body, underslung mouth and an adhesive organ on the belly formed from their fused pelvic fins.

The Homaloptera-group are more loach-like. Although some experts reckon these should be lumped in with the balitorines due to some shared features. Homaloptera, in general, feed on invertebrates. They probably live in slower flowing water than balitorines like the Chinese plec.

Nemacheilines, could easily be mistaken for "real" cobitid loaches. One of them - the Stone loach, Barbatula barbatula - lives in rivers in the UK.

We've seen quite a few new balitorids in recent shipments from India. If you have a rummage through your dealer's tanks you could find some very unusual fishes.

Do Chinese plecs eat algae?

Balitorines usually feed on aufwuchs rather than the algae itself, so they may not make a huge difference to the amount of algae visible in the tank. Aufwuchs is a collective name for microscopic invertebrates that live within the tufts of algae. Most balitorines will accept frozen bloodworm, brine shrimp and tablet foods or even flakes, but lush green algae is appreciated.

Are they coldwater?

Not as such. Most of those in the shops are really tropical fish. Some have a high requirement for oxygen, and because warmer water holds less oxygen than cold water, they do better in cooler tanks. They are highly unlikely to survive outdoors.

For best results keep them around the 20C mark. If you keep them warmer you'll need to take special care to ensure the water is very well oxygenated.

What conditions do they like?

Many species are relatively small, so any aquarium over 60cm/24" is usually fine. Ideally this ought to have a substrate of fine sand or fine gravel and be furnished with smooth rounded pebbles and small boulders.

Balitorines like Chinese plecs, are designed to live in very fast flowing white water regions. You are unlikely to be able to recreate realistic biotope conditions in an aquarium, but to get as close as you can, add a battery of powerful internal power filters to provide flow and keep the water oxygen rich.

Ideally, the pH ought to fall between 6.5-7.5 - although many will happily go over pH 8 and seem quite adaptable regarding pH and hardness levels. Keeping the oxygen level high is the most important factor.

Other more loach-like balitorids can be kept quite successfully in the average community aquarium. They seem far less demanding and are often pretty easy to keep.

What is their behaviour like?

Balitorids are really interesting fish to watch. Although peaceful, most will defend territories, either to sequester feeding resources like a nice patch of algae, or to keep other fish away from a potential breeding site. Some balitorines chase other fish, especially rival males and non-breeding females, out of their area but I've never seen them physically harm other fishes.

A few of them, such as some Schistura species I've kept, can be a little aggressive and even drive larger fishes out of their territory.

How do Chinese plecs stay attached to rocks?

Chinese plecs and other balitorines are equipped with a ventral sucker-disc. This is a specially modified set of fins that form a suction cup on the underside of the fish. When the fish settles on a rock, it wiggles its fins to push out water and creates a mini-vacuum which sticks it in place.

The fish can slide over smooth rocks, and can even wriggle over wet rocks out of the water still "stuck" to the rock. This allows the fish to feed in very fast-flowing white water.

They can probably feed from places in a river that other fishes can't even get near to because of the speed of the water flow.

The balitorines seem to be very difficult to catch. What's the secret?

Despite their slug-like appearance these fish are capable of an amazing turn of speed. This coupled with the ability to stick firmly to rocks and the aquarium glass makes them virtually impossible to remove from the tank.

To catch them, remove all of the decor from the tank apart from a single rounded stone, and then coax the fish off the glass using a net. Eventually it will stick to the rock. You can then pick up the rock with the fish still attached, while holding the net underneath. As you reach the surface, the fish will drop off and land in the net.

Have they been bred in captivity?

Yes, although like cobitid loaches, they aren't easy to breed and spawning successes are pretty rare. One PFK reader managed to spawn a balitorine species (Pseudogastromyzon cheni) in her coldwater community tank a few years ago and we have heard of some other reports too.

How do you sex balitorines?

It depends on the species. Males are usually more colourful and may have coloured edges to the dorsal fin, which are more drab in females. Some species also develop patches of odontode-like bristles on the head. These are clearly visible in Gastromyzon ctenocephalus, which is sometimes called the Spiny-headed hillstream loach as a result.

How do you breed them?

Balitorines spawn in a depression in the substrate, alongside a pebble or rock. The male wiggles about a bit to excavate a little hollow in the gravel.

Little is known about how to get them to spawn, since most spawnings have occurred by chance. It seems logical that you might be able to trigger them to breed by conditioning them with plenty of food for a couple of months, and then performing a water change using cooler water.

What species are available?

While only one or two species appear on the import lists that the aquatic shops use to order their fish from abroad with, there are actually many more species imported, most of which come in as bycatch mingled in with other fishes from the region.

There are also a number of currently undescribed species on sale in the shops.

To track down the unusual ones you'll usually have to closely study your dealer's tanks. It's very rare to see any balitorids offered for sale under anything other than a made-up common name. While this can make finding particular species a bit difficult, it does make fish shopping trips very interesting, as you never know what you might find mixed in with the common varieties.

This article was published in the August 2003 issue of Practical Fishkeeping.