8 letter answer(s) to cousin of a stickleback SEAHORSE.
What is a Penguins cousin?
The most likely answer for the clue is AUK.
What is a Sticklebat?
: any of a family (Gasterosteidae) of small scaleless bony fishes having two or more free spines in front of the dorsal fin and including marine, anadromous, and freshwater forms.