Home | Aquarium Livestock | Fish for the Cold Water Aquarium – the Oriental Weatherfish Misgurnus anguillicaudatus & the European Weatherfish Misgurnus fossilis

Fish for the Cold Water Aquarium – the Oriental Weatherfish Misgurnus anguillicaudatus & the European Weatherfish Misgurnus fossilis

Please welcome back Frank Indiviglio for another article.
During our last discussion of cold water aquariums, we looked at 2 interesting marine species, the oyster toadfish and the Atlantic spider crab. Today I’ll write about the natural history of the weatherfishes, ideal candidates for an unheated fresh water aquarium.

Weatherfishes do not receive nearly the attention they deserve from aquarists, often being purchased as “curiosities” or “scavengers”. This is unfortunate, as they are among the most interesting of all fishes, and are very hardy as well. Their inquisitive dispositions and readiness to feed from the hand can only be described as “charming”. In part 2 of this article we will learn more about how to keep and enjoy them in the aquarium.

Two species are regularly available – the European weatherfish and the Oriental weatherfish (also sold as the dojo loach or Japanese weatherfish). The Oriental weatherfish is more commonly seen in the pet trade in the USA.

Physical Description
Weatherfishes have elongated, eel-like bodies with 5 pairs of fleshy barbels (sensory organs) surrounding the mouth. Their color ranges from metallic and golden tan through various shades of brown. The European species is striped, while the Oriental weatherfish is largely spotted, but both exhibit a mixed pattern of these markings. The Oriental weatherfish is also available in gold and albino color morphs.

Each can reach 12 inches in length, but rarely exceed 8 inches in the aquarium. I at first thought this was be due to a poor diet, i.e. their having to subsist upon “leftovers”. However, a number of individuals of both species that I have kept (including an Oriental weatherfish that reached age 21) also topped out at that length, despite being fed a diet rich in insects, snails and aquatic worms. I did see animals of 12-13 inches in a food market in a Chinese community in NYC. I was told that they had been imported from Hong Kong, but the store owner did not know whether they had been wild-caugClown Loachht or farm-raised. Perhaps, as with other fish species, local populations or races vary greatly in size.

Weatherfishes are classified as loaches, in the family Cobitidae. Many of the 118 species in this family of fresh water fishes, including the coolie loach, clown loach, yo-yo loach and hill stream loach, are popular with aquarists.

Range and Habitat
Both species have a huge range and are equally at home in many types of waterways. The European weatherfish favors rivers, streams and lakes, but is able to tolerate farm ponds and other less-than-ideal habitats as well. The Asian species is found in every type of fresh water environment imaginable. Due to its ability to take oxygen from the air, it is found in stagnant waters and does quite well in swamps, ditches and rice fields.

The Oriental weatherfish occurs from southern Russia south through India and China to Vietnam, Korea and Japan and has been introduced to Australia, Germany, the Philippines, Palau and the USA (Hawaii, California, Idaho, Indiana, Illinois). Much to the horror of loach fanciers, it is used as fish bait in some places, a fact that may in part account for the widespread feral populations. Detailed fieldwork has not been carried out with regard to introduced populations. However, as ravenous predators of invertebrates and fish eggs, it is suspected that they are negatively affecting local species. For this reason, weatherfishes are illegal to possess in Australia and England.

The European species occupies most of Europe except for Great Britain, Ireland, Scandinavia and Greece. Introduced populations have been found in Italy, Spain, Croatia and the USA (Great Lakes region and possibly elsewhere).

Both species feed largely upon insects, snails, worms and terrestrial invertebrates that fall into the water. They will also feed upon carrion and likely take fish eggs and fry as well.

Rising temperatures and water levels stimulate breeding in both species. Pairs perform “mating dance” of sorts during which the male wraps himself about the female and fertilizes the eggs as they are laid. The eggs are greenish in color and attach to plants and the substrate. No parental care is provided.

The weatherfish owes its common name to its unique habit of becoming very active just before a storm. This activity apparently is caused by the effects of barometric pressure (change in air pressure) upon the swim bladder. Weatherfish are among the earliest fish species to have been maintained in captivity – farmers in medieval Europe kept them for their weather predicting abilities, and in Japan they were much valued for their habit of swimming to the water’s surface prior to earthquakes.

Weatherfishes can breathe atmospheric oxygen, a facility that allows them to survive in swamps, rice fields and other habitats unsuitable for many fishes. Interestingly, they have evolved a respiratory system that is quite different than that employed by the “labyrinth breathers” (gouramis), lungfishes and other species that utilize air-borne oxygen. When breathing from the water’s surface, weatherfishes gulp air, absorb its oxygen within the gut and expel the excess via the anus.

During droughts, both species aestivate by burrowing into the mud, where they survive without water for quite long periods. Weatherfishes living in temperate areas spend the cooler seasons below the mud as well.

Please write in with your questions. I am very interested in hearing from you concerning the sizes your weatherfishes have reached, or if you have observed large individuals in food markets. Thanks, Frank.

An interesting article about introduced populations of the Oriental weatherfish (here and abroad) is posted at:http://www.thefreelibrary.com/New+records+for+the+alien+oriental+weatherfish,+Misgurnus…-a0162455040

Thanks Frank,
Until Next Time,


  1. avatar

    I’m very interested in buying some of these fish, but how much are they and can i just feed them the normal fish food flakes? Please reply to my email address, its unlikely i’ll be able to find this page later on, sorry, thanks.

  2. avatar

    I scooped an oriental from the Illinois River, Brandon Rd. pool today (7-27-2010). I could see at least 5 others swimming in a bed of eelgrass. I just put him in a 30 gal tank with small gravel. I used tap water but treated it with dechlorination drops. I am going to try feeding it some “bottom feeder” sinking tablets from PetCo. We’ll see what happens.

  3. avatar

    Hi … I’m from Europe and has been involved in biology European Weather Loach.I am a breeder of this fish, and I know a lot of the prevalence of…among others, Poland, Germany, Holland, Belgium, Denmark, Lithuania, Latvia and Estonia.It is very interesting fish which in ancient times had mythological significance.In old Europe, people thunderfish they dried and used as torches because they contained a lot of fat is long on fire giving a large flame.The rural population was holding the fish in different containers of water to warn before the storm.It is without doubt the most resistant fish oxygen deficit, can live in a very small amount of water or buried in the mud a few months and survive the severest winter.He was listed in the Red Book of protected species in Europe.

  4. avatar

    Thanks so much for your insightful response!!

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.