Final answer:
The astrological creature often described as being half fish, half goat is known as a Capricorn.
Step-by-step explanation:
The astrological creature often described as being half fish, half goat is known as a Capricorn. In Greek mythology, Capricorn is represented as a creature with the head and upper body of a goat and the tail of a fish. It is one of the twelve zodiac signs and is associated with the period from December 22 to January 19.