About the Weather Loach
Species Type: Freshwater Fish
Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.
Origin: Asia, native to Siberia, Sakhalin, Korea, Japan, China, northern Vietnam. Has been introduced to many countries including Australia, those in North America and some in Europe. Found in rivers, lakes, ponds, swamps and rice fields; prefers still or slow-moving water and a mud substrate and thick vegetation.
Compatibility/Temperament: Relatively peaceful, but it is predatory and may eat smaller fish. This species is very social and should never be kept singly but always in a small group of at least three. It can be maintained with peaceful upper fish that are not too small to be eaten and that can manage in the cooler temperature.
The Dojo Loach--the name "dojo" is the Japanese for loach--is also seen under the alternate common name "weather loach" that is shared with several other members of the genus Misgurnus and the spotted weather loach (Cobitis taenia, commonly known as Spined Loach), and arose from their ability to detect changes in barometric pressure and react with frantic swimming or standing on end. This is because before a storm the barometric pressure changes, and this is known to make these fish more active.
The colouring and patterning can be quite variable from fish to fish. This fish is a popular food fish in its native countries. In the aquarium, they can be "friendly" toward humans, allowing physical contact and hand feeding.
As noted under Origin, this fish has been introduced into many countries and there are reports of adverse ecological impact. It is illegal in some states like Michigan, please check state legislature about this fish before purchasing.
A suitable aquarium must be at least 4 feet in length for a group of three, with a sand or very fine smooth gravel substrate to allow this fish to bury itself. This fish will often be very active; the tank must be well covered, as this fish will frequently jump. Decor can include large smooth rocks and bogwood to provide shelter, but rocks must be securely placed as this fish will dig under objects. Plants will likely be uprooted, so these should be restricted to floating plants, and these will also dim the light. Dried leaves can be scattered on the substrate. The filter flow should be moderate, sufficient to provide oxygen but not a strong current out of deference to this species' habitat conditions.
This species was described in 1842 by T.E. Cantor and placed in the genus Cobitis. In 1949, Berg moved it into the current genus that was erected by B.G.E. Lacepede in 1803. A number of distinct species and subspecies were described through the late 19th and early 20th centuries but these are now deemed conspecifics and the names are synonyms of the subject species. The exact number of species in this genus is unknown.
If the Botiinae subfamily is raised to distinct family status as some have proposed [see comments in the profiles of the Botia loaches], the Cobitinae subfamily would then be the family Cobitidae. This name comes from the Greek kobitis [= sardine].
Weather Loach Diet
Naturally feeds on worms, small crustaceans, insects, insect larvae, and other small aquatic organisms. In the aquarium, weather loaches are omnivorous and will accept most prepared sinking foods but should also be fed some live or frozen worms, brine shrimp, snails and earthworms.
Normally 9 to 10 inches but can reach a foot in length.
Minimum Tank Suggestion
4 feet in length.
Ideal water parameters for Weather Loach
Soft to medium hard (< 12 dGH), basic (pH 7 to 8) though some sources include slightly acidic (pH 6-7), temperature 10-25C/50-77F. This is not a tropical species and must be kept within the stated temperature range, and preferably not at the high end for extended periods.