Island has endless fish, great seen from below (8)
I believe the answer is:
sardinia
'island' is the definition.
(I know that Sardinia is an island)
'endless fish great seen from below' is the wordplay.
I cannot quite see how this works, but
'fish' could be 'sar' (I've seen this before) and 'sar' is found in the answer.
'from' could be 'in' (I've seen this in other clues) and 'in' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'has' is the link.
Can you help me to learn more?
(Other definitions for sardinia that I've seen before include "Island south of Corsica" , "Adrian is seen in Mediterranean island" , "Island belonging to Italy" , "Corsican neighbour" , "Second-largest Mediterranean island, after Sicily" .)