In general, fish under 50lbs only need a gaff hook with a gap measuring 2” to 3”, but on some species such as dorado, king mackerel, barracuda and other slim-bodied species, a 2” hook is almost always the best choice. Fish over 50lbs should be gaffed using a 3” or 4” hook. On some species such as sharks, large tuna and jumbo cobia, 4” is best.
