A halibut's a type of flatfish from the family of the right-eye flounders (Pleuronectidae). This name's derived from haly (holy) and butt (flat fish), alleged to be called so from being commonly eaten on holy-days. Halibut live in both the North Pacific and the North Atlantic oceans and are highly regarded food fish. Physical characteristics The Halibut's the largest of all flat fish, with an average weight of about 11 - 13.5 kg (25 - 30 lb), but they can grow to be as much as 196 kg (431 lbs… (More on Halibut)