Meal for a seal (3)
I believe the answer is:
eel
'meal for a seal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eel that I've seen before include "Ribbon-like fish" , "Large elver" , "Wriggly fish" , "elusive person" , "Proverbially slippery fish" .)