Brackish would be good, a twenty would hold a couple of the smaller inshore sculpins and the only thing bigger than their mouths are their appetites. I catch 3" inch fish on 4" lures quite often. Most sculpins are bottom lurking ambush predators and the often mouth wrestle with each other, cheap and amusing, And if you don't use a heater you can use natives from the washington coast or puget sound, there are many types ranging in max size from under 2" to over 2".