Overview
The weather loach, also called the dojo loach, is a long, eel-shaped bottom dweller from the cool streams, ponds and rice paddies of East Asia. Peaceful, hardy and full of personality, it slithers through the substrate, drapes itself over decor and often becomes tame enough to be hand-fed.
Its nickname comes from a curious habit: weather loaches become restless and dart about when the barometric pressure drops before a storm. They are cool-water fish that suit an unheated tank and make gentle companions for goldfish and other pond species.
| Care level | Beginner |
| Adult size | 6-8 in (15-20 cm) |
| Lifespan | 10+ years |
| Temperament | Peaceful and playful |
| Min. tank | 30 gal (114 L) |
| Temperature | 50-77 F (10-25 C) |
| pH | 6.5-8.0 |
| Hardness | 5-19 dGH |
| Diet | Omnivore (bottom feeder) |
| Schooling | Social, keep 3 or more |
Water & tank conditions
Weather loaches are cool-water fish comfortable across a wide range, from around 50 F up to the low 70s, so they need no heater and even tolerate an outdoor pond in mild climates. They are sensitive to poor water and to medications, so keep the tank clean and well cycled, and cover it, since they are escape artists.
Aquascape & setup
Give them a SOFT sand or fine, smooth substrate to burrow into, along with caves, wood and plants for cover. They love to dig and hide, so avoid sharp gravel that damages their skin and barbels, and secure the lid, since they will find any gap.
Diet & feeding
Omnivorous bottom feeders that eat sinking pellets and wafers, frozen bloodworms and tubifex, and will happily snack on pest snails. Make sure food reaches the bottom, as they forage on the floor rather than at the surface, and offer a varied diet for good health.
Tankmates & temperament
Peaceful, social and best kept in groups of three or more, where they pile together and play. They are ideal cool-water companions for goldfish, white cloud mountain minnows and other calm species, and are far too gentle to bother tankmates.
Breeding
Weather loaches rarely breed in home aquariums and are usually farm-raised. In ponds a cool period followed by warming can trigger spring spawning, with eggs scattered among plants, but home breeding is uncommon and not something most keepers attempt.
Fun facts
- Weather loaches get their name from becoming lively and restless when air pressure drops before a storm.
- They can gulp air at the surface and absorb oxygen through their gut, letting them survive in low-oxygen water.
- These loaches are notorious escape artists and will slip through any small gap in the lid.
- They often become tame enough to eat from their keeper's hand and to be gently held.
- In a mild climate they can live happily in an unheated outdoor pond alongside goldfish.
Frequently asked questions
Do weather loaches really predict the weather?
Sort of. They become restless and swim about wildly when the barometric pressure drops ahead of a storm, a real reaction to falling pressure that earned them their name.
Do weather loaches need a heater?
No. They are cool-water fish comfortable from about 50 F into the low 70s, so they suit an unheated tank and even a mild-climate pond.
What do weather loaches eat?
They are omnivorous bottom feeders. Offer sinking pellets and wafers, frozen bloodworms and tubifex, and they will also eat pest snails, as long as food reaches the bottom.
Do weather loaches need to be in groups?
Yes. They are social and are far happier and more active in groups of three or more, where they rest and play together.
Can weather loaches live with goldfish?
Yes. Their cool-water needs and gentle temperament make them one of the best tankmates for goldfish and other calm cool-water fish.
