A lot of fishy food generating terror (5)
I believe the answer is:
scamp
'terror' is the definition.
(both can mean a naughty child)
'a lot of fishy food' is the wordplay.
'a lot of' means to remove the last letter (most of the word but not all of it).
'fishy food' becomes 'scampi' (type of seafood).
'scampi' with its final letter taken off is 'SCAMP'.
'generating' acts as a link.
(Other definitions for scamp that I've seen before include "Impish child" , "little monkey" , "Scallywag" , "pickle" , "A young rascal misbehaving in camps" .)