Assistants like eating fish (5)
I believe the answer is:
aides
'assistants' is the definition.
(aide is a kind of assistant)
'like eating fish' is the wordplay.
'like' becomes 'as'.
'eating' indicates putting letters inside.
'fish' becomes 'ide' (type of fish).
'as' placed around 'ide' is 'AIDES'.
(Other definitions for aides that I've seen before include "Helpers" , "Right-hand men" , "Ministerial assistants" , "Adjutants" , "Helpful officers" .)