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.
Click on any of the images below to view our Loach gallery.