It is a small fish with a thick body, with a large head and tapering body. It has four long spines - two on each side on the gill cover - that stick out when the fish is removed from the water. It has a variety of colours ranging from shades of browns, with cream blotches, but sometimes orange or red with white blotches.
Bullhead are predators that will eat prawns, molluscs an other fish. Despite their small size they are aggressive and will attack fish bigger than themselves. They lie in wait for prey, camouflaged against rocks and weed before striking out at anything that passes. Like all fish in the Cottidae family the Bullhead does not have a swim bladder, meaning that it sinks as soon as it stops swimming.
Other English names for this species include sea scorpion, bullhead, rockfish, rock sculpin, scorpion fish, clobberhead.