Stream bullhead

Identification

The Rhine sculpin is a small, stocky bottom fish of 8 to 15 cm with a broad, flattened head and a body tapering toward the rear. The large pectoral fins are fan-shaped and serve as supports on the bottom. Brown to grey-brown with dark marbling providing excellent camouflage. Eyes sit high on the head. Only described as a separate species from the common bullhead (Cottus gobio) in 2005.

Behavior & ecology

Lives on the bottom of fast-flowing, shallow streams with gravel or stone substrate. Hides motionless among rocks by day; hunts insect larvae, freshwater shrimp, and worms at night. Territorial: males defend a cavity under a stone where eggs are deposited and guarded. Lacks a swim bladder — moves in short sprints along the bottom.

In the Netherlands

Protected under Dutch nature conservation law. Found in fast-flowing streams in southern Limburg and the Twente stream system. With 205 records, well documented. An indicator for ecologically healthy stream ecosystems.