Fish one caught in comfort (6)
I believe the answer is:
solace
'comfort' is the definition.
(I know that comfort can be written as solace)
'fish one caught in' is the wordplay.
'fish' becomes 'sole' (sole is a kind of fish).
'one' becomes 'ac' (I can't explain this - if you can you should give a lot more credence to this answer).
'caught in' indicates putting letters inside.
'sole' enclosing 'ac' is 'SOLACE'.
Can you help me to learn more?
(Other definitions for solace that I've seen before include "Comfort at a time of sadness" , "Comport" , "Something that comforts distress" , "Comfort in time of disappointment or sorrow" , "console" .)