The locathah first appeared in the 1975 Blackmoor supplement.
The locathah appeared in first edition Advanced Dungeons & Dragons in the original Monster Manual (1977).
The locathah appeared in second edition in the Monstrous Compendium Volume Two (1989), and reprinted in the Monstrous Manual (1993). The locathah appeared as a player characterrace for the Forgotten Realms setting in Sea of Fallen Stars (1999).
The locathah appeared in the third edition Monster Manual (2000), and in the 3.5 revised Monster Manual (2003).
Although humanoid in shape, locathahs are clearly more fish than human. The average locathah stands 5 feet tall and weighs 175 pounds. Females and males look very much alike, although the former can be recognized by the two ochre stripes marking their egg sacs.