Fish right inside channel (6)
I believe the answer is:
trench
'channel' is the definition.
(I've seen this before)
'fish right' is the wordplay.
I cannot really understand how this works, but
'right' could be 'r' (abbreviation) and 'r' is present in the answer.
'fish' could be 'tench' (tench is a kind of fish) and 'tench' is found within the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'inside' acts as a 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" .)