Fish right inside channel (6)
I believe the answer is:
trench
'channel' is the definition.
(I've seen this in another clue)
'fish right' is the wordplay.
I cannot really see how this works, but
'right' could be 'r' (common abbreviation) and 'r' is found within the answer.
'fish' could be 'tench' (tench is a kind of fish) and 'tench' is present in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'inside' is the link.
Can you help me to learn more?
(Other definitions for trench that I've seen before include "deep channel" , "Long, narrow excavation" , "It may be slit" , "at the front" , "Drain" .)