Melanocetus johnsonii is a species of fish in the family Melanocetidae, the black seadevils. It is known commonly as the humpback anglerfish, humpback blackdevil, and Johnson's anglerfish. It is a deepwater fish living at depths of up to 4500 meters, but generally remaining above 1500 meters. It is native to all the oceans of the world, where it can be found in tropical and many temperate regions. It is even known from the Ross Sea in Antarctica. First discovered by and named after James Yate Johnson.