Bullheads in my area (North Ontario)are called "Brown Bullheads" by the MNR. My grandfather always called them Barr-butts and they were a type of catfish, about a foot long at most. Some of my earliest memories are of fishing for them at night with my dad and grandpa, sitting on a wide culvert in the dark at Twin Lakes, St Joseph Island, struggling to hold a long heavy bamboo cane pole across my knees and hoisting up a 2 pound Barr-butt over my head onto the road behind. We kept going till we has a big metal washtub full. Took about 2 hours. Good eating, if you got `em early enough in the season before they got too wormy. They can live long out of water too. They'd be croaking (the sound, not the cease-to-be vernacular) all night long in the tub (no water in it) and still be flipping around in the morning when we went out to clean `em in the morning. Cleaning was a real chore. You had to use pliers to peel the thick scaleless skin off them and snap off the three spines at the root.

Dogfish was another name locally for what was also called lush, ling, bowfin or snake. Big, ugly, slow, useless and full of shit which they squirted all over your boat when you hauled them in. Best to just cut the line near the hook, if you were baitfishing.

Near as I can tell, the UK bullhead is what we call here a mudpout (and the biology books call a sculpin). Used to catch tons of `em by turning over rocks in the creeks and ditches around here when I was a kid. Made good bait for bass, pike and pickerel (which the Yanks call walleye). Haven't seen one in years. Crayfish was good bait too and could be found by the same method. Same with bloodsuckers (leeches).