Stone Loach are long, slim shape, having 3-pairs of barbules around their under slung mouth, their backs and flanks have black mottling over a dark olive brown colouration, fading to a narrow grey/white belly. They are small fish with an average length of just 8-10cm. Their superb camouflage does not assist easy location in the shallows and polaroids and great patience will be needed to spot them.
Stone Loach usually inhabit flowing stretches of streams and medium-sized rivers with gravel or stone bottoms, but are sometimes found in sandy canals and the shallows of well oxygenated lakes with stony shallows. They will inhabit fast flowing waters and pools, but prefer to spawn in the shallow, fast flowing riffles.
They are found throughout most of Europe, except in the extreme north and south, in stony streams and rivers, and into Eurasia. They are sensitive to low oxygen levels and pollution, especially the presence of heavy metals.
They feed on small invertebrates and insect larvae.
A 2-3 year old female Stone Loach is believed to spawn approximately 10,000 sticky yellow eggs per female, shed amongst the sand, stones and aquatic vegetation on the bed or the stream or river. Spawning can take place several times a year when water temperatures reach between 8 – 18°C, between late April – early August. Dependant upon habitat, the young fish can reach approximately 6cm in the first year and 10cm by the end of the second year.
The Stone Loach is quite a short-lived species, averaging 3-4 years, with a 5-year old fish being uncommon.
Their preferred habitat in the fast shallows combined with their very small size, is likely to make bite detection quite difficult, even with tiny hooks and very light tackle, but worth a go if the fish are located. They are normally caught by accident and sometimes caught when the river is above normal levels by fishing right in the edge of the flow where they can seek shelter in the bank side vegetation.
They live in the River Wey stretches, so have a go there if you want to try and catch one.