Stone Loach

About

The stone loach is a small, whiskery, brown-marbled bottom fish of clean flowing streams, and in Lithuania it is one of the most ordinary fish there is — Lithuanian Wikipedia calls it common here and describes it living in a great many rivers and streams with sand or stone on the bottom, hidden among rocks, roots and plants for most of the day. It has three pairs of barbels on the lower jaw, eyes set high on the head, and no spine under the eye, which is what separates it from the spined loach. FishBase records a maximum of 21 cm and Wikipedia agrees, though it also says the typical fish is around 12 cm and Lithuanian Wikipedia puts adults at 10–12 cm, rarely 15. The number that matters for anyone buying one is not the length but the thermometer: FishBase's climate row for this species reads 'Temperate; ? - 18°C'. This is a coldwater animal. It is also an oxygen snob — FishBase notes it is sensitive to pollution and low oxygen and that its presence in a river is taken as an indication of good water quality — and it is a facultative or obligate air breather that will come up for a gulp. In a heated tropical community tank at 25 °C it does not die on the first day; it declines quietly over months in water that is too warm and too still to hold the oxygen it needs, which is exactly why a shop shelf is a dangerous place to meet one.

Care

Cold, fast, clean water — not a tropical tank, and not a heater. Plan on 120 litres and 90 cm of length for a river-style set-up: rounded gravel and cobbles it can hide under, a powerhead or a large filter return giving real current, heavy aeration and no heater at all. FishBase's band tops out at 18 °C, so the honest home is an unheated room, a cellar tank or a chiller; anything above about 20 °C for months on end is the slow killer. Keep it with other coldwater fish or with nothing — it is peaceful and completely uninterested in tankmates, it will not touch plants, and it eats invertebrates, not algae, so it cleans nothing. Feed sinking food after dark. Cover the tank: it breathes air at the surface and it is an eel-bodied fish in current, which is the profile that finds gaps. Legally, this is a Lithuanian native that is not on the country's protected species list (the fish that are: Atlantic sturgeon, whitefish, nase, lake minnow, weatherfish and Baltic golden loach) and is not a target of commercial or sport fishing here; Lithuanian Wikipedia notes that in some western European countries it is rare and protected, so if you live elsewhere check your own national rules before collecting one.

Diet

Nocturnal invertebrate hunter: gammarids, chironomids and other insect larvae taken off the bottom by touch and smell. Feed sinking frozen and granular foods after lights out. Not an algae eater.

Telling males from females

There is no reliable way to sex this species by eye. That is the honest answer, not a gap in our data.

Also in these lists

Similar species

Same category and the closest water parameters — if this species isn't quite it, start here.

Sold in Lithuania

These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.

These links are unpaid: we get nothing for them and ask for nothing.

Frequently asked questions

What tank size does a Stone Loach need?

A Stone Loach needs an aquarium of at least 120 litres (31.7 US gallons) with a footprint at least 90 cm (35.4 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Stone Loach need?

Stone Loach does best at 2–18 °C (35.6–64.4 °F), pH 6.5–8 and a general hardness of 8–18 °dGH.

Is the Stone Loach suitable for beginners?

Stone Loach is a demanding species best attempted with some experience — it needs stable, closely watched conditions to thrive.

Sources

• FishBase — Barbatula barbatula (Stone loach)
• Wikipedia — Stone loach
• Vikipedija — Šlyžys
• Lietuvos raudonoji knyga — Lietuvos Respublikos saugomų gyvūnų, augalų ir grybų rūšių sąrašas 2020 m.