sea monkey n.

1909 as a heraldic animal, 1964 as a U.S. proprietary name for brine shrimp (Artemia salina), which had been raised as food for aquarium fish but were marketed as pets by U.S. inventor Harold von Braunhut (1926-2003), who also invented "X-Ray Specs" and popularized pet hermit crabs. He began marketing them in comic book advertisements in 1960 as "Instant Life," and changed the name to Sea Monkeys in 1964, so called for their long tails.