Scientific name
Cottus gobio
Popular name
Bullhead
Description
The bullhead is a species of fish that often lies under the stones, living in clear mountain streams and rivers, its presence being an indicator of high water quality. Its body is elongated and thick, with a length of 8-10 cm, the head is large, flattened and thicker than the body, the eyes are protruding and looking up and the small brush shape teeth are distributed on multiple rows. It has two uneven dorsal fins, joined by a bridge and it has no scales. The characteristic color is olive brown, with marbled spots and 3-4 dark transversal stripes, very obvious in light color specimens.
Food
Being a bentofag predator (it feeds on species living on the bottom of the water), the bullhead feeds on insect larvae, amphipods, spawn and fish eggs, occasionally frog eggs.
Reproduction
The bullhead reaches sexual maturity in 2 years. The reproduction takes place during spring, in March-April, the female laying 100-300 large eggs. The males “dig” a cavity under the stones, where they guard the eggs until they hatch, after 4-5 weeks. Therefore, the presence of stones in the waterbed is very important for this species, also the water has to be clean and cold and connectivity and shelter areas are also necessary.
Habitat
It lives exclusively in fresh, cold, mountain waters, mostly in rivers and streams, rarely in mountain lakes. It lies under stones, in areas with less deep and slow water, often to the bank or in side arms. Strictly sedentary, bullhead does not migrate. It barely moves and, if disturbed, it moves for a short distance. The presence of woody vegetation on the shore is very important for this species: roots, wood remains and leaves fallen in the waterbed provide shelter areas. Also, the foliage provides shade, otherwise the bullhead is very exposed to water heating.
Distribution
The bullhead is spread from England and northern Spain to the Balkans and the Crimean Peninsula, generally on the upper course of most rivers that spring from the mountains.
