Aquarium Tropical Fish Articles
Loaches have a heightened sense of taste and smell as well as some very flexible body shapes. They will search out stray food wherever it falls. They are nocturnal, but they are great scavengers, especially appreciated by the aquarist. Loaches almost always adapt to aquarium foods and are long lived, with many species can live 10 years or more. They can win your affection and respect, as they do a great job keeping the bottom of the aquarium clean.
Although popularly known as Loaches or true Loaches, these fish have also been commonly referred to as "Thorn-eyes". This is because they have one or two thorn-like spines directly between the eyes or just beneath the eyes. These spines are often erect and can act as a defense, be careful when catching these fish. These spines often gets caught in the net
The true Loaches belong to the family Cobitidae. There are quite a few species available to aquarists, yet this is a rather small family. It consisting of about 100 species, but it does contain some of the most spectacular freshwater fishes. They are found in rivers throughout Asia, Europe, and parts of Africa. They occur throughout much of the Old World, widely across southern and southeast Asia. Only 3 are native to Germany and just a few species are found in northern Africa, mostly in Morroco and Ethopia.
There are a number of similarities found between the Loaches and their close relatives the Hillstream Loaches, such as multiple barbels around the mouth. The HIllstream Loaches, like their name suggests, occur in mountain streams and belong to the Balitoridae family. Occasionally both Hillstream Loaches and Loaches are confused with the catfishes because of the presence of barbels. One similarity that lends to this confusion are the number of barbels, all of these fish have between 3 to 6 pairs. Another is the appearance of being scaleless due to very tiny scales on some species. Yet all these fish are in fact covered with scales or partially covered with scales. Catfish on the other, are without scales, most often protected with bony plates instead.
The Loach species list below includes popular varieties as well lesser known loaches. Each fish guide has in-depth loach information including their places of origin, habitats and behaviors as well as the fish care needed for successfully keeping them in the aquarium. Fish pictures are also provided within each fish guide to help with identification, and to aid in choosing Loach fish as pets.
For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care
Most of the loaches are not very large, being only a few inches, but there are exceptions with a few of the Botia reaching over 12" (30 cm) and the exceptionally large Royal Clown Loach which can reach up to 20" (50 cm). The body forms, though most often elongated and rather cylindrical (and a few that are flattened), are quite varied. They can be chunky and heavy, worm-like, or even eel-like.
For the most part these fish are bottom dwellers, but many species have a unique intestine that can act as a respiratory organ similar to that of the Corydoras. This allows them to absorb oxygen at the surface directly from the atmosphere, a feature that helps ensure survival even if water conditions are polluted or are oxygen depleted.
Some Cobitidae species were believed to be extremely sensitive to atmospheric pressure so that when the weather changed they would get quite active, swimming up and down in the aquarium. These fish have been used as living barometers and are referred to as 'weather fish'. A noted example is the Dojo Loach,Japanese Weather Fish, or Weather Loach. It is uncertain however, whether these nervous displays are from a barometric change, some other change in conditions, or just their unique behavior.
These fish mainly get active in the evening or after dark, are mostly bottom feeders, and are omnivores. Although in their natural habitat many primarily eat insect larvae, live worms, and crustaceans, they also nibble on algae and other vegetation. They can be fed dry flake food, freeze dried and frozen proteins such as tubifex and bloodworms, and vegetable substitutes such as a soft algae or algae wafers. Some of the larger species of Botia are fond of Red Ramshorn snails and occasionally a Mystery snail.
They all prefer hiding places where they can retreat to at will. The worm-like species especially like to hide under plant roots or wood while the free swimming species like to hide in caves.
There is little known about the reproduction of most of these fish. Though there have been some reported successes of breeding loaches among various hobbyists, it is mostly a matter of chance and these fish are not yet commercially bred.