Starfish (6)
I believe the answer is:
pisces
'starfish' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Maybe there's a link between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for pisces that I've seen before include "Spice for the Fish" , "'Sign of the zodiac, the fish (6)'" , "Fish star sign" , "The twelfth sign of the zodiac, the fishes" , "Twelfth zodiacal sign" .)