This is the broadest-spread loach.
Spined loaches grow a little over 10 cm. Its body is compressed on the sides, particularly at head. The coloration is motley: rows of large rounded and rectangular spots on the sides compose a visible line against the flaxen background. Eye to snout, there is a dark-brown, almost black line. At base of the upper blade of the fin, there is a dark stroke. Spined loaches settle in quiet, shallow river reaches and lake bays, and are also present in shallow brooks where it is easy to spot and observe. It prefers sites with oozy sand, which is easy to dig into, as well as thickets of filamentous algae, where it hovers in a peculiar curve. It changes color to match the soil: if it digs up, it is hardly visible – only the moving opercula tell its position. Its mouth is downward, small, lined with soft bladed lips. It feeds on bottom crustaceans – macrothricidae and chydoridae; testate amoebas – difflugia and arcella; smaller wrigglers. Spined loaches are most active in the evening. They also have their intestinal respiration developed well, but not quite as well as the European weather loach.
The fish spawns in the water of at least 16°С, mainly in June and July. The intermittent spawning takes 1-2 months. Eggs do not weigh much, and therefore they develop suspended in filamentous algae. Fry hatch on days 4-6, depending on the temperature, and remain in the algae thick. Similarly to European weather loach fry, they develop external gills soon after hatching. Fry actively forage on the small crustaceans – chydorae – abundant in filamentous algae. Reaching 18-20 mm in length, spined loaches enter the bottom phase of life. The most favorable years for spawning are the ones with high summer temperatures and abundant filamentous algae.
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