Fish found in a creel sometimes (4)
I believe the answer is:
eels
'fish' is the definition.
(eel is a type of fish)
'in a creel sometimes' is the wordplay.
'in' indicates a hidden word.
'EELS' is hidden in the letters of 'creel sometimes'.
'found' acts as a link.
(Other definitions for eels that I've seen before include "Smooth fishes" , "Sea snakes among lees" , "Elongated fish" , "Snakes found in lees" , "Slippery creatures" .)