As seen in the constellation Pisces? (8)
I believe the answer is:
starfish
'as seen in' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'constellation pisces?' is the wordplay.
'constellation' becomes 'star' (I can't explain this - if you can you should believe this answer much more).
'pisces?' becomes 'fish' (I've seen this in another clue).
'star'+'fish'='STARFISH'
'the' is the link.
Can you help me to learn more?
(Other definitions for starfish that I've seen before include "Marine echinoderm" , "Marine creature with five arms" , "As swimmer" , "Has rifts (anag)" , "Well-armed customer" .)